Astaro
Security Linux
WebAdmin
User Manual
Astaro
Security Linux V5
(Version 5.000)
User Manual
Release 1.0 – Date: 06.04.2004
The specifications and information in this document are subject to
change without notice. Companies, names, and data used in
examples herein are fictitious unless otherwise noted. This document
may not be copied or distributed by any means, in whole or in part,
for any reason, without the express written permission of Astaro AG.
© Astaro AG. All rights reserved.
Pfinztalstrasse 90, 76227 Karlsruhe, Germany
http://www.astaro.com
Portions © Kaspersky Labs.
Astaro Security Linux and WebAdmin are trademarks of Astaro AG.
Linux is a trademark of Linus Torvalds. All further trademarks are the
property of their respective owners.
Limited Warranty
No guarantee is given for the correctness of the information contained
in this document. Please send any comments or corrections to
documentation@astaro.com.
Table of Contents
Contents
Page
1.
Welcome to Astaro ................................................ 9
2.
Introduction to the Technology ........................... 10
3.
Installation .......................................................... 18
3.1.
System Requirements .......................................... 19
3.2.
Installation Instructions ...................................... 22
3.2.1.
Software Installation ........................................... 22
3.2.2.
Configuring the Security System.......................... 27
4.
WebAdmin ........................................................... 34
4.1.
Info Box............................................................... 35
4.2.
Tab List................................................................ 35
4.3.
Menus .................................................................. 36
4.3.1.
The Status Light................................................... 36
4.3.2.
Selection Fields.................................................... 36
4.3.3.
Drop-down Menus................................................ 38
4.3.4.
Lists..................................................................... 39
4.4.
Online Help .......................................................... 40
4.5.
Refresh ................................................................ 41
5.
Using the Security System ................................... 42
5.1.
Basic Settings (System)....................................... 44
5.1.1.
Settings ............................................................... 44
5.1.2.
Licensing ............................................................. 50
5.1.3.
Up2Date Service .................................................. 54
5.1.4.
Backup................................................................. 62
5.1.5.
SNMP Access........................................................ 68
5.1.6.
Remote Syslog Server.......................................... 69
5.1.7.
User Authentication ............................................. 71
5.1.7.1.
RADIUS................................................................ 72
5
Table of Contents
Contents
Page
5.1.7.2.
SAM – NT/2000/XP ............................................. 76
5.1.7.3.
LDAP Server......................................................... 78
5.1.8.
WebAdmin Settings ............................................. 91
5.1.9.
WebAdmin Site Certificate ................................... 94
5.1.10.
High Availability .................................................. 97
5.1.11.
Shut down/Restart ............................................ 102
5.2.
Networks and Services (Definitions) ................. 103
5.2.1.
Networks ........................................................... 103
5.2.2.
Services ............................................................. 110
5.2.3.
Users ................................................................. 114
5.3.
Network Settings (Network).............................. 118
5.3.1.
Hostname/DynDNS............................................ 118
5.3.2.
Interfaces .......................................................... 119
5.3.2.1.
Standard Ethernet Interface .............................. 124
5.3.2.2.
Additional Address on Ethernet Interface .......... 128
5.3.2.3.
Wireless LAN ..................................................... 130
5.3.2.4.
Virtual LAN ........................................................ 140
5.3.2.5.
PPPoE-DSL Connection ...................................... 145
5.3.2.6.
PPTPoE/PPPoA-DSL Connections....................... 150
5.3.3.
Routing .............................................................. 155
5.3.4.
NAT/Masquerading............................................ 157
5.3.4.1.
NAT.................................................................... 157
5.3.4.2.
Masquerading .................................................... 161
5.3.4.3.
Load Balancing .................................................. 163
5.3.5.
DHCP Server ...................................................... 165
5.3.6.
PPTP VPN........................................................... 169
5.3.7.
Accounting......................................................... 175
5.3.8.
Ping Check ......................................................... 177
5.4.
Intrusion Protection .......................................... 179
5.4.1.
Settings ............................................................. 179
6
Table of Contents
Contents
Page
5.4.2.
Rules ................................................................. 182
5.4.3.
Advanced ........................................................... 186
5.5.
Packet Filter ...................................................... 188
5.5.1.
Rules ................................................................. 188
5.5.2.
ICMP .................................................................. 200
5.5.3.
Advanced ........................................................... 203
5.6.
Application Gateways (Proxies)......................... 207
5.6.1.
HTTP/Surf Protection ........................................ 208
5.6.2.
DNS ................................................................... 225
5.6.3.
SOCKS................................................................ 227
5.6.4.
POP3.................................................................. 229
5.6.5.
Ident ................................................................. 234
5.6.6.
SMTP ................................................................. 235
5.6.6.1.
Virus Protection/Content Filter.......................... 240
5.6.6.2.
Spam Protection ................................................ 247
5.6.7.
Proxy Content Manager ..................................... 251
5.7.
Virtual Private Networks (IPSec VPN) ............... 256
5.7.1.
Connections ....................................................... 265
5.7.2.
Policies .............................................................. 273
5.7.3.
Local Keys.......................................................... 277
5.7.4.
Remote Keys...................................................... 280
5.7.5.
L2TP over IPSec................................................. 283
5.7.6.
CA Management................................................. 285
5.7.7.
Advanced ........................................................... 290
5.8.
System Management (Reporting) ...................... 293
5.8.1.
Administration ................................................... 293
5.8.2.
Virus .................................................................. 294
5.8.3.
Hardware........................................................... 294
5.8.4.
Network............................................................. 295
5.8.5.
Packet Filter ...................................................... 296
7
Table of Contents
Contents
Page
5.8.6.
Content Filter..................................................... 296
5.8.7.
PPTP/IPSec VPN................................................ 297
5.8.8.
IPS .................................................................... 297
5.8.9.
Executive Report ............................................... 297
5.8.10.
Accounting......................................................... 298
5.8.11.
System Information........................................... 300
5.9.
Local Logs (Log Files) ........................................ 302
5.9.1.
Settings ............................................................. 302
5.9.2.
Local Log File Query........................................... 306
5.9.3.
Browse .............................................................. 307
5.9.3.1.
Log Files ............................................................ 311
5.9.3.2.
Error Codes........................................................ 315
5.10.
Online Help ........................................................ 328
5.11.
Exiting the Security Solution ............................. 329
Glossary .............................................................................. 330
Index .................................................................................. 337
8
Welcome to Astaro
1. Welcome to Astaro
Congratulations on your purchase of the Internet Security Solution
Astaro Security Linux V5, and welcome to the Astaro family.
This manual will take you step-by-step through the installation process, will explain the web-based WebAdmin™ configuration tool, and
can be used to document your configuration.
The most recent version of this document is always available at the
following address:
http://docs.astaro.org
In order to provide you with the most up-to-date information possible, this document makes occaisonal reference to other documents
available at the web sites of Astaro and other organizations. Please
note that these addresses may change over time, and that documents
hosted by other organizations may even be removed entirely.
If you have further questions, or notice any mistakes in this manual,
please do not hesitate to contact us at
documentation@astaro.com
For further support, please visit our user support forum at
http://www.astaro.org
or make use of the Astaro Support Program.
9
Introduction to the Technology
2. Introduction to the Technology
Before exploring the Astaro Security Linux Security Solution in detail,
it may be helpful to take an overview of network and security technology in general. In particular, it is important to understand the
serious risks that unprotected systems face as well as where and how
to deploy this security system to mitigate these risks.
Networks
The Internet is already well established as a vital communications
medium and a key marketplace for both traditional and new services.
Since its inception, its size has multiplied, with domain name growth
between 1995 and 2002 reaching almost exponential proportions.
Computers on this worldwide network communicate using the
Internet Protocol (IP), as well as various higher-level protocols
such as TCP, UDP, and ICMP. IP addresses uniquely identify each of
the computers reachable on the network.
The Internet itself is a collection of smaller networks of various kinds.
When two or more networks are connected, a number of issues arise
which are dealt with by devices such as routers, bridges, and
gateways. A firewall is another such device, designed with security in
mind.
As a rule, three kinds of network meet at the firewall:
•
An external or Wide Area Network (WAN)
•
An internal or Local Area Network (LAN)
•
A De-Militarized Zone (DMZ)
An example configuration is shown on the next page.
10
Introduction to the Technology
The Firewall
One of the components in this security system is a firewall. The
characteristic tasks of a firewall connecting a WAN, LAN, and DMZ
are:
•
Protection against unauthorized access
•
Access control
•
Collection of audit trails
•
Protocol analysis
•
Reporting of security-related events
•
Concealing internal network structure
•
Separation of servers and clients using proxies
11
Introduction to the Technology
•
Guaranteeing information confidentiality
A firewall combines several network components in order to provide
these assurances. The following is a brief look at some of these tools
and their uses.
Network-Layer Firewalls: Packet Filters
As the name suggests, this component filters IP packets on the basis
of source and destination address, IP flags, and packet payload. This
allows an administrator to grant or deny access to services based on
factors such as:
•
The source address
•
The destination address
•
The protocol (e.g. TCP, UDP, ICMP)
•
The port number
The primary advantages of packet filters are their speed and their
independence of operating systems and applications in use behind the
firewall.
Advanced implementations of packet filters also inspect packets at
higher network layers. Such filters interpret transport-level information (such as TCP and UDP headers) to analyze and record all
current connections. This process is known as stateful inspection.
A stateful packet filter records the status of all connections, and
allows only those packets associated with a current connection to
pass. This is especially important for allowing connections from a
protected network to an unprotected one, but disallowing connections
in the opposite direction.
When a computer in the protected network establishes a connection
with an external server, the stateful packet filter will allow the
server’s response packets in to the protected network. When the
original connection is closed, however, the packet filter will block all
12
Introduction to the Technology
further packets from the unprotected network (unless, of course, they
have been explicitly allowed).
Application-Layer Gateways: Application Proxies
The second main kind of firewall is the application-layer gateway.
These gateways act as a middleman in connections between external
systems and protected ones. With such gateways, packets aren’t forwarded so much as translated and rewritten, with the gateway
performing the translation.
The translation process on the gateway is called a proxy server, or
proxy for short. Because each proxy serves only one or a few welldefined application protocols, it is able to analyze and log protocol
usage at a fine-grained level, and thereby offer a wide range of
monitoring and security options.
The analysis can be especially intensive at the application level,
because the application data transferred conforms to standardized
protocols. The firewall knows about and can inspect every aspect of
the data flow. This also means that small, manageable modules can
be used for each kind of data, which in turn means the system is less
prone to problems due to implementation errors.
For example, this security solution includes the following proxies:
•
An HTTP proxy with Java, JavaScript and ActiveX
•
An SMTP proxy, which scans e-mails for viruses and controls email distribution
•
A SOCKS proxy which acts as a generic authenticating circuit-level
proxy for many applications
Application-level gateways have the advantage of allowing the
complete separation of protected and unprotected networks. They
ensure that no packets are allowed to move directly from one network
to the other. This results in reduced administration costs: as proxies
ensure the integrity of protocol data, they can protect all of the clients
13
Introduction to the Technology
and servers in your network, independent of brand, version, or
platform.
Protection Mechanisms
Some firewalls contain further mechanisms to ensure added security.
One such mechanism is supporting the use of private IP addresses in
protected networks through Network Address Translation (NAT),
specifically
•
Masquerading
•
Source NAT (SNAT)
•
Destination NAT (DNAT)
This allows an entire network to hide behind one or a few IP
addresses, and hides the internal network topology from the outside.
This allows internal machines
to access Internet servers while
making
it
identify
individual
is
impossible
to
machines
from the outside.
Using Destination NAT, it is
nevertheless possible to make
internal or DMZ servers available to the outside network for
specific services.
Example:
An
external
user
(see graphic on left) with the IP
address 5.4.3.2 sends a request from port 1111 to the
web server in the DMZ. The
user knows only the external IP
and port (1.1.1.1, port 88).
Using DNAT, the firewall changes the destination address of the
14
Introduction to the Technology
request to the internal address of the web server (10.10.10.99, port
80), and sends it to the web server. The web server then responds,
using its own internal IP address (10.10.10.99), and sends the reply
back to the user. The firewall recognizes the packet from the user’s
address and changes the source address of the reply from the web
server’s address to its own external address (1.1.1.1, port 88).
Another advanced protection mechanism supported by this system is
VPN technology. To meet the demands of modern business, IT
infrastructures must offer real-time communication and allow close
cooperation between business partners, consultants, and branch
offices. Increasingly, these demands are being met through the use of
extranets, which usually operate either
•
via dedicated lines, or
•
unencrypted over the Internet.
Each of these approaches has advantages and disadvantages which
must be balanced according to cost and security requirements.
15
Introduction to the Technology
Virtual Private Networks (VPN) provide a cost-effective solution to
this problem: they can connect LANs over the Internet using encrypted connections, thus enabling secure, transparent, end-to-end
communication without the need for leased lines. This is especially
useful when an organization has many branch offices connected to the
Internet. IPSec technology provides a standard model for these
secure connections.
These secure connections can be used automatically, independent of
the data being transferred – this protects the data without requiring
extra configuration or passwords on the client systems.
16
Introduction to the Technology
At the other end of the connection,
the
transparently
data
is
decoded
and
forwarded to the recipient in its
original form.
The Firewall component of this
security system is a hybrid of
the
preceding
mechanisms,
protection
combining
the
advantages of each:
The
Packet
Stateful
Filter
Inspection
offers
the
platform-independent flexibility
to define, enable, and disable all necessary services.
The Proxies incorporated into this security system transform it into
an Application Gateway capable of securing vital services such as
HTTP, Mail and DNS. Further, the SOCKS proxy enables generic
circuit-level proxying for all proxy-aware applications.
VPN, SNAT, DNAT, Masquerading and static routing capabilities
make the firewall a powerful connection and control point on your
network.
17
Installation
3. Installation
The installation of this Internet security solution proceeds in two main
steps: loading the software, and configuring the system parameters.
The initial configuration required for loading the software is performed
through the console-based Installation Menu, while the final
configuration and customization can be performed from your management workstation through the web-based WebAdmin interface.
While configuring your system, please note that the
WebAdmin
system
pro-
vides additional information
and help through its Online
Help system. To access this
system,
simply
click
the
button marked ?.
The following pages contain
configuration
worksheets
where you can enter the
data (such as default gateways and IP addresses) you use to set up
your system. We recommend you fill these out as you configure the
system, and that you keep the worksheets in a safe place for future
reference.
Attention:
If you are upgrading your system from version 4 to version 5, and
you wish to keep the settings from your existing installation, you
must first upgrade your system to version 4.021 at least. Only
backup files from this or higher versions of Astaro Security Linux can
be loaded into Version 5. Further information on the Up2Date Service
and the Backup function can be found in chapters 5.1.3 and 5.1.4.
18
Installation
3.1. System Requirements
The requirements for installing and using this security system are:
Hardware
•
Processor: Pentium II or compatible (up to 100 users)
•
Processor: Pentium III or compatible (up to 100 users)
•
256 MB RAM
•
8 GB IDE or SCSI hard drive
•
Bootable IDE or SCSI CD-ROM drive
•
2 or more PCI Ethernet network cards
•
For wireless LAN access: a wireless LAN PCMCIA card with the
Prism2 chipset (or compatible)
Important Note:
The High Availability (HA), Wireless LAN, and Virtual LAN subsystems require extra hardware. Please check the Hardware
Compatibility List for Astaro Security Linux, available at
http://docs.astaro.org for compatibility.
To make Heart Beat Monitoring of the High Availability (HA)
system easier, we recommend using network cards that support link
beat for all interfaces. The installation of the HA system is described
in detail in chapter 5.1.10 on page 97.
19
Installation
Administration PC
Correct configuration of the Default Gateway, IP Address, and
Subnet Mask
An HTTPS-compliant browser (Microsoft Explorer 5.0 or newer,
Netscape Communicator 6.1 or newer, or Mozilla 1.6+)
JavaScript and Cascading Style Sheets must be activated.
In the browser configuration, no proxies should be configured for
the IP address of the eth0 interface on the firewall.
Example Configuration
As in the diagram on the
left, the security system
should be the only link
between the internal and
external networks.
20
Installation
Address Table
IP Address
Network Mask
Internal
network
interface
___.___.___.___
___.___.___.___
External
network
interface
___.___.___.___
___.___.___.___
___.___.___.___
___.___.___.___
___.___.___.___
___.___.___.___
DMZ
network
interface
1)
Network
interface for
the HA
system 2)
Default Gateway
___.___.___.___
1)
The third and further network cards are optional.
2)
Network interface for the High Availability system.
21
Installation
3.2. Installation Instructions
What follows is a step-by-step guide to the installation process.
Attention:
The installation process will destroy all existing data on the hard disc!
Preparation
Before installation, please make sure you have the following items
ready:
•
•
The security system CD-ROM
The Address Table, with all IP Addresses, Netmasks and
Default Gateway filled in
3.2.1.
Software Installation
The first part of the installation uses the Installation Menu to configure basic settings.
The setup program will check the hardware of the system (see
screenshot), and then install the necessary software on your PC.
1.
Boot your PC from the CD-ROM drive (Step 1):
In order to navigate through the menus, use the following keys.
Please note the additional key functions listed in the green bar at
the bottom of the screen.
Cursor keys: Use these keys to navigate through the text boxes
(e.g., the license agreement or when selecting a keyboard
layout)
Enter key: The entered information is confirmed, and the
installation proceeds to the next step.
22
Installation
ESC key: Abort the installation.
Tab key: Move between text boxes, entry fields, and buttons.
Attention:
The installation will destroy all data on the PC!
2.
Keyboard Layout (Step 2):
Use the Cursor keys to select your keyboard layout and press
Enter to continue.
3.
Hardware Test (Step 3):
The software will check the following hardware requirements:
CPU, size and type of hard drive, CD-ROM drive, network cards,
and IDE or SCSI controllers.
If your system does not meet the minimum requirements, the
installation will report the error and abort.
4.
License Agreement (Step 4):
Note:
Please read the license agreement carefully.
Press F8 to agree to the terms of the license.
5.
Time and Date (Step 5):
Use the Cursor keys to select your country and press Enter to
confirm.
Use the Cursor keys to select your time zone and press Enter to
continue.
Next, enter the current time and date in the entry field. Use Tab
and the Cursor keys to switch between entry fields. Invalid
entries will be rejected.
Confirm your entries with the Enter key.
23
Installation
6.
Network Card Selection and Configuration (Step 6):
In order to use the WebAdmin tool to configure the rest of your
security system, you must now configure a card to be the internal network card (eth0).
Choose one of the available network cards from the list and
confirm your selection with the Enter key.
Next, define the IP Address, Network Mask, and Default
Gateway for this network card.
Example:
Address: 192.168.2.100
Netmask: 255.255.255.0
You must enter a value in the Gateway field if you wish to use
the WebAdmin interface from a workstation outside the subnet
defined by the netmask. Note that the gateway itself must be
within the subnet.
For example, if you are using a netmask of 255.255.255.0, the
subnet is defined by the first three values of the address: in this
case, 192.168.2. If your administration computer is at, for
example, 192.168.10.5, it is not on the same subnet, and thus
requires a gateway to be configured here. The gateway router
must have an interface on the 192.168.2 subnet, and must be
able to contact the administration computer.
In our example, assume the gateway is at 192.168.2.1:
Gateway: 192.168.2.1
If the administration computer is on the same subnet as the
internal network card (in our example, if its address is
192.168.2.x) it does not need a gateway. In this case, enter the
following value here:
Gateway: none
Confirm your entries with the Enter key.
24
Installation
7.
Final Notes (Step 7):
Attention:
Please read the notes and warnings presented during the
installation carefully. After confirming them, all existing data on
the PC will be destroyed!
If you wish to change your entries, press F12 to return to Step
1. Otherwise, start the installation process by pressing the Enter
key.
8.
Installing the Software (Step 8):
The software installation process can take up to a couple of
minutes. You can follow the progress of the installation using the
four monitoring consoles:
There are four consoles available:
Main Installation (Alt + F1).
Interactive bash Shell 1(Alt + F2).
Installation Log (Alt + F3).
Kernel Log (Alt + F4).
When the installation process completes, remove the CD-ROM
from the drive and connect the eth0 network card to the internal
network.
Except for the internal Network card (eth0), the sequence of
network cards normally will be determined by PCI ID and by the
Kernel drivers.
The sequence of network card names may also change if the
hardware configuration is changed, especially if network cards
are removed or added.
25
Installation
9.
Reboot the System
Reboot the security system by pressing Ctrl + Alt + Del or the
Reset button.
During the boot process, the IP addresses of the internal network
cards are changed. The Install Routine console (Alt + F1) may
display the message No IP on eth0 during this time.
After the security system has rebooted (a process which, depending
on hardware, can take up to five minutes), ping the IP Address of the
eth0 interface to ensure it is reachable.
If no connection is possible, please check for the following possible
problems.
Error:
The security system is not reachable from the internal network.
Possible Causes:
•
The IP Address of the security system is incorrect
•
The IP Address of the client computer is incorrect
•
The Default Gateway on the client is incorrect
•
The network cable is connected to the wrong network card
•
All network cards are connected to the same hub
Note:
If you connect to the Internet through a DSL connection, please read
the installation instructions at docs.astaro.org.
26
Installation
3.2.2.
Configuring the Security System
The rest of the configuration will use the WebAdmin interface,
accessed through a standard web browser (e.g., MS Internet
Explorer) from your administration PC:
1.
Start your browser open WebAdmin
Before you can access the WebAdmin interface, you must make
sure that your browser is configured correctly. Please see in
chapter 5.6.1 on page 208 for more details.
Once your browser is correctly configured, start it and enter the
management address of the security system (the internal IP
address configured for eth0) as follows: https://IP Address.
(In
the
example
from
step
6
above,
this
would
be
https://192.168.2.100)
A security notice will appear. When you generate a certificate
for WebAdmin in a later step, this notice will disappear.
Further information on generating and installing certificates can
be found in chapter 5.1.9 on page 94.
For now, simply accept the security notice by clicking the Yes
button.
The first time you start WebAdmin, two windows will open: the
first contains the License Agreement, and the second is used
for Setting system passwords.
2.
Complete the License Agreement
In the License Agreement window, accept the terms of the
license by clicking the I agree to the terms of the license
selection box.
Note:
Please read the terms of the license carefully.
27
Installation
3.
Set the System Passwords
In the Setting system passwords window, enter the passwords for the Internet security system.
Security Note:
Use a secure password! Your name spelled backwards is,
for example, not a secure password – while something like
xfT35$4 would be.
You will only be able to start WebAdmin once you have entered
passwords for the functions listed below. Enter the password for
each service, and then re-enter it in the text field labeled
Confirm. The usernames are pre-defined, and cannot be
changed.
WebAdmin user: access to WebAdmin
This user is called admin.
Shell Login user: access to SSH
This user is called loginuser.
Shell Administrator user: administrator privileges in the entire
security system.
This user is called root.
Security Note:
Use different passwords for the Shell Login and Shell
Administrator users.
Astaro Configuration Manager User (optional): You need
this password, if you wish to configure the Security system with
the Astaro Configuration Manager.
If set, the password will prevent unauthorized users from changing boot-time parameters.
Confirm the entered passwords by clicking Save.
28
Installation
Boot Manager (optional): This password prevents meddlers
from changing the boot parameters.
Confirm the passwords by clicking on the Save button.
4.
Log in to WebAdmin
User: admin
Password: Password of the WebAdmin user
Please note that passwords are case-sensitive!
Click Login.
Note:
Please follow steps 5 through 15 in the order listed below.
5.
Configure Basic Settings
In the System tab, open the Settings menu and enter the following setting :
Administrator E-Mail Addresses: Enter the e-mail address of
the administrator here.
You can find further information about these functions in chapter
5.1.1 on page 44.
In the Network tab, open the Hostname/DynDNS menu and
enter the following settings in the General System Settings
window:
Hostname: Enter the Hostname for this security system.
A domain name may contain alphanumeric characters, periods,
and hyphens. The end of the name must be a valid top-level
domain, such as “com”, “de”, or “org”. The Hostname will be
included in all Notification E-Mails.
Save the settings by clicking Save.
29
Installation
6.
Configure the Internal Network Interface (eth0)
In the Network tab, open the Interfaces menu and check the
settings for eth0.
The settings for this network card are based on the information
entered during the software installation. After starting the
security system, they are shown in the Current Interface
Status window.
If you wish to change
settings for this card, for
example
changing
the
configured name, please
open the Edit Interface
window by clicking the edit button and make these changes
now.
Attention:
If you misconfigure the IP Address of the eth0 network card,
you may be locked out of WebAdmin.
The configuration of network cards and virtual interfaces is
described in chapter 5.3.2 on page 119.
7.
Configure the Internal Network
In
the
Definitions
tab, open the Networks
menu
and
check the settings for
the internal network. Three logical networks were defined during
installation based on your settings for the internal network card
(eth0):
The interface Internal (Interface), consisting of the defined IP
address (example: 192.168.2.1) and the host network mask
255.255.255.255.
30
Installation
The internal network Internal (Network), consisting of the
defined IP address (example: 192.168.2.1) and the defined
network mask (example: 255.255.255.0).
The broadcast network Internal (Broadcast), consisting of the
broadcast
address
(example:
192.168.2.255)
ad
the
host
network mask 255.255.255.255.
Defining new Networks is described in chapter 5.2.1 on page
103.
8.
Configure the External Network Card
In the Network tab, open the Interfaces menu and configure
the interface to be used to connect to the external network
(Internet). The choice of interface and the required configuration
depend on what kind of connection to the Internet you will be
using.
The configuration of network cards and virtual interfaces is
described in chapter 5.3.2 on page 119.
9.
Define Masquerading Rules
If you wish to use private IP addresses for your internal network
and wish to connect directly (without proxies) to the Internet,
you can now establish the relevant rules in the Network/
NAT/Masquerading menu.
More information about DNAT, SNAT and Masquerading can
be found in chapter 5.3.4 on page 157.
IP routing entries for networks directly connected to the security
system’s network cards (Interface Routes) will be added
automatically.
If required, you can also define routing entries manually using
the Routing menu. This will, however, usually only be necessary
in complex network environments.
31
Installation
10. Configure the DNS Proxy
In order to speed up name resolution, you can specify a local
DNS name server (or one provided by your ISP) in the
Proxies/DNS
menu.
Otherwise,
the
security
system
will
automatically use the root name servers.
If you wish to use the proxy, you should configure the DNS
Proxy settings now.
More information about configuring the DNS Proxy can be found
in chapter 5.6.2 on page 225.
11. Connect Other Networks
If you wish to connect other internal networks to the security
system, attach their cables now.
12. Configure the HTTP Proxy
If computers on the internal network should use the HTTP proxy
to connect to the Internet, open the HTTP menu in the Proxies
tab and click Enable.
The configuration of the HTTP proxy is described in more detail
in chapter 5.6.1 on page 208.
Please note that the computers on the internal network will have
to be configured to make use of the proxy.
13. Configure the Packet Filter
In the Rules menu under the Packet Filter tab, you can
establish packet filtering rules.
By default, all packets are filtered until you explicitly enable
certain services. New rules are added to the bottom of the list,
and are inactive until explicitly enabled. The rules are processed
starting with the first and moving down the list, stopping at the
first applicable rule. To activate a rule, click the status light once
– the status light will turn green.
Please note that, because the security system uses Stateful
32
Installation
Inspection, only the connection-building packets need be
specified. All response packets will automatically be recognized
and accepted.
Configuring the Packet Filter is described in chapter 5.5 on
page 188.
14. Debug Packet Filter Rules
With the Packet Filter Live Log function In the Packet Filter/
Advanced menu, you can see which packets the packet filter is
filtering. If you have problems after installing your security
system, this information can be helpful in debugging your
filtering rules.
The Packet Filter Live Log function is described in chapter
5.5.3 on page 203.
15. Install System and Virus Scanner Updates
You should download and install the latest System Up2Dates as
soon as possible.
If you have a license for the Virus Protection module, you
should also run the Pattern Up2Date system.
The Up2Date Service option is described in chapter 5.1.3 on
page 54.
When you’ve completed these steps, the initial configuration of your
security system is complete. Click the Exit tab to leave WebAdmin.
Problems
If you have problems completing these steps, please contact the
support department of your security system supplier, or visit the
Astaro Bulletin Board at:
http://www.astaro.org
33
WebAdmin
4. WebAdmin
The WebAdmin tool allows you to configure every aspect of the
Astaro Security Linux system. This chapter explains the tools and
concepts used by WebAdmin, and shows how to use the built-in
online help system.
WebAdmin has four main components:
(1) Info Box
(2) Tabs
(3) Menus
(4) Online help
(5) Refresh
34
WebAdmin
4.1. Info Box
The system time and time
zone are always displayed in
the top left-hand corner of
the screen. If you roll the
mouse over the time display,
the
Info
Box
will
appear,
containing the following information:
Uptime: Displays how long the security system has been running
without a restart.
User: Displays which user is currently logged in to WebAdmin, as
well as the client the user is logged in from.
Last Login: Displays when and from which client WebAdmin was
last used.
4.2. Tab List
The Tab List on the left of the screen
organizes
the
various
menus
ac-
cording to subject. To list the menus
contained under a subject heading,
simply click the tab: the available
menus will appear below. For ease of
use, chapter 5, “Using the Security
system”,
has
been
structured
to
match the order of topics in the Tab
List.
35
WebAdmin
4.3. Menus
Every function of the security system has its own separate menu in
WebAdmin. This chapter describes the tools and displays used in the
configuration menus.
4.3.1.
The Status Light
Many features and subsystems of the security system
can be enabled or disabled
while the system is running.
A status light displays the
current status of such subsystems:
•
red = Function is disabled
•
green = Function is enabled
For many features, the configuration options and tools will not be
displayed until the status light is green.
4.3.2.
Selection Fields
There are two kinds of selection field which are used in configuring
the security system.
Selection Fields like the one at
the left, called here type A, are
used to select arbitrary groups of
things like users or networks. This
kind of field is used, for example, when selecting Allowed Networks
or Allowed Users.
36
WebAdmin
Adding Objects to the Selected List:
1.
In the Available list, select the object (e.g. the network or user)
you wish to add by clicking its name.
You can select more than one object at a time by holding the
CTRL key while you make your selection.
2.
Click the Left Arrow button.
The names you selected in the Available window will be moved
to the Selected window.
Removing Objects from the Selected List:
1.
In the Selected list, choose the objects (networks or users) you
wish to remove by clicking them.
Again, you can select more than one object at a time by holding
the CTRL key while you make your selection.
2.
Click the Right Arrow button.
The objects will be moved back to the Available window.
The second kind of Selection
Menu (type B) is used to append
objects to a list, for example
Authentication
Methods
or
Network Interfaces.
As a rule, the administrator must first configure these objects. If
there are objects available, the drop-down list in the selection menu
will display the message Select to append; otherwise, it will read
Empty List.
37
WebAdmin
Appending Objects to the List:
1.
Open the drop-down menu.
2.
Choose the object to add by clicking its name.
The name will be moved to the list immediately.
Removing Objects from the List:
1.
Double-click the name of the object to be removed.
The object will be moved back to the drop-down menu
immediately.
4.3.3.
Drop-down Menus
Drop-down menus are used to
configure functions that can have
only one of a few values. To use,
simply select the value from the
list: as a rule, values chosen in
drop-down
immediately.
38
menus
take
effect
WebAdmin
4.3.4.
Lists
Lists are used, in contrast, to
configure functions that not only
allow more than one value to be
configured, and where the listed
objects do not need to be first
defined by the administrator. In
some instances, the order of the
configured values is also relevant.
Each list can contain many pages
of values, and each page displays
ten entries.
The Interfaces menu, for instance, uses a list to allow access to the
Wireless LAN Access Point.
The first row of the table shows
the number of pages in the list on
the
left
(the
current
page
is
shown in white) and the total
number of entries on the right
(next to the # symbol). Note
that, if you roll the mouse over one of the red page numbers, a tooltip
appears showing the first and last entries on that page. (See picture
at right.) This can help to navigate quickly between pages.
The second row contains tools to control the display of the list. Note
that these do not change the configuration information, but rather the
way in which these entries are displayed within WebAdmin. In cases
where order is important, only the order indicated by the numbers
next to entries has an effect on the configuration of the function. The
buttons
and
in the left-hand column display the list in ascending
and descending numerical order respectively, while the
and
buttons in the middle column display the list in ascending or
descending alphabetical order.
39
WebAdmin
The functional order, as indicated by the numbers to the left of each
entry, can be adjusted using the buttons in the right-hand column. A
click on the
or
button in this column will move the entry one row
up (i.e., towards 1) or down (towards the end of the list) respectively.
Similarly, you can move an entry to the very beginning or end of the
list by clicking the
or
buttons in this column, respectively.
Add entry: Type a value in the text-entry field and click Add.
The new value will appear in the last row of the table.
Delete entry: By double-clicking an entry, you can remove it from
the list.
Edit entry: If you click an entry once, it will appear in the entry field.
Edit the entry as desired and click the Replace button to put it back
into the list.
4.4. Online Help
Every menu in WebAdmin
has an Online Help screen
which
provides
a
short
explanation of the available
configuration options.
You
can
open
the
help
screen by clicking the ?
button at the top righthand corner of the screen.
40
WebAdmin
4.5. Refresh
To load the menu again,
click the Refresh button.
Don’t use the Refresh
button of the tool bar of
your browser to actualize
the menu – otherwise
you are logged-off the
session and have to log
in again under the WebAdmin
configuration
tool!
41
Using the Security System
5. Using the Security System
We have already seen the
web-based
configuration
tool WebAdmin in action
during
the
installation
process. This chapter will
describe
how
WebAdmin
to
to
use
control
and monitor your security
system on a day-to-day
basis.
The specific settings, what they do, and how to change them will be
described step-by-step. Please look to chapter 4 for a more general
description of how to use the tools provided by the WebAdmin
interface.
Please remember that the goal in configuring a security system like
this should be to enable only the features necessary for correct
functionality. In general, you should restrict in- and outbound
connections to those explicitly required.
Tip:
Draw up a plan of your network and determine which computer is to
have access to which services before configuring the security
system. This will simplify the configuration process and save you a
lot of time.
Configure the system as follows:
1.
Define all the required networks and hosts.
2.
Define the necessary services.
3.
Define the system rules and proxies.
42
Using the Security System
Starting WebAdmin:
1.
Start your browser and enter the address of the Security system
(i.e., the address of the eth0 interface) as follows:
https://IP Address.
In our example from step 6 of the installation instructions in
chapter 3.2, this would be https://192.168.2.100.
If you have not yet generated a Certificate for your WebAdmin
site, a Security notice will appear.
More information on how to install a certificate is available in
chapter on page 94.
2.
Click the Yes button on the security notice to continue.
3.
Log in to WebAdmin.
User: admin
Password: the password
of the WebAdmin user.
Both entries are case-sensitive!
4.
Click Login.
Another administrator is already logged-in:
If another administrator is
already
logged
in
to
WebAdmin, a notice will
appear on screen. The IP
address shows you which
computer the other administrator is using.
The kick function allows you to end the other administrator’s
session.
In the Reason field, type a reason for ending the other user’s
session and click Login.
43
Using the Security System
You are now logged in, and can use the WebAdmin to manage the
system.
5.1. Basic Settings (System)
The menus under the System tab allow you to configure and manage
the basic settings of your Security Solution.
5.1.1.
Settings
Administrator Contact
E-Mail Addresses: Whenever
certain important events occur,
such as portscans, failed logon
attempts, or reboots, as well as whenever the self-monitor or Up2Date systems generate alerts or reboots, the security system will
send a notification e-mail to the administrator through the e-mail
addresses entered into the ordered list. At least one e-mail address
must be present; otherwise the E-Mail Reporting module will be
disabled.
To add a new e-mail address, enter it in the entry field and click Add.
Please see chapter 4.3.4 on page 39 to learn more about the
functions of the ordered list.
Important Note:
Notification E-Mails can only be sent to the administrator when the
DNS Proxy is enabled and configured (chapter 5.6.2 on page 225), or
when the SMTP menu (chapter 5.6.6 on page 235) has been
configured with a route for incoming e-mails.
Use external Indicators: This option is only available on appliance
systems with an attached LCD indicator. This option allows you to
turn the LCD display on or off.
44
Using the Security System
Time Settings
This menu can be used to set
the time and date of the security system. The date and time
can be set manually with the
help of the drop-down menu or
can be automatically synchronized using the NTP-server (Network
Time Protocol). Please note that important changes in the time setting
will appear as gaps in the Reporting and Logging.
Important note:
We do not recommend changing the system time for daylight savings
time. Instead, we recommend setting the system clock to Central
European Time (CET). In summer, this corresponds to a deviation of
less than one hour.
When system time settings are changed, the following “time warp”
effects may be noticeable:
Moving forward (e.g., standard time to daylight saving time)
•
The timeout for WebAdmin will expire and your session will no
longer be valid.
Time-based reports will have no data for the skipped hour. In most
graphs, this time period will appear as a straight line in the
amount of the old value.
•
Accounting reports will contain values of 0 for all variables during
this time.
Moving backward (e.g., daylight saving time to standard time)
•
There are already log data for the corresponding span of time in
the time-based reports that for system purposes come from the
future: These data will not be overwritten.
•
Log data will be written as normal when the time point before the
reset is reached again.
45
Using the Security System
•
Most diagrams will display the values recorded during this period
as compressed.
•
Accounting reports will retain the values recorded from the
“future”. Once the time point of the reset is re-reached, the
accounting files will be written again as normal.
Because of these difficulties, we recommend that the time be set only
during the first configuration, and that only minor adjustments be
made later. We recommend setting the system clock to Central
European Time (CET). This is the original time. The system then runs
always in CET, not in in CEST (Central European Summer Time). We
recommend, not to change the time for summer, especially not when
the collected reporting and accounting data are treated.
Manual configuration of system time:
1.
Open the Settings menu in the System tab.
2.
In the Time Settings window make the following settings in the
given order:
Use NTP Server: In order to configure the system clock
manually, please ensure that No NTP Server is selected here. In
this case, the Please select drop-down menu will be displayed.
If a NTP Server is selected, select No NTP Server from the
drop-down menu.
Time Zone: Now select the time zone.
Note:
Changing the timezone will only change the current system time
if you are using an NTP server to control time settings.
Use slow adjustment: When this function is selected, the
security system will attempt to minimize the “time warp” effects
mentioned above.
46
Using the Security System
Note:
When resetting, the system time will be adjusted to the newly
set time in small steps. When the time differences are large, this
adjustment process can last days or even weeks.
Set Time: Enter the current date and time here.
Important note:
Take note of the issue date of your License Key. If this date is
after the current date set on the security system, the license will
be deactivated.
The 30-day Evaluation License will not automatically activate.
5.
Click the Save button to save these settings.
The time settings of the security system will now be updated.
Synchronizing system time with NTP Server
Before the system clock of the Internet security system can be
synchronized with an external server, this server must be defined as
NTP Server. The NTP Server will be defined as a network consisting
of only one computer.
The definition of networks is covered in greater detail in chapter 5.2
on page 103. If the NTP server has already been defined, please
begin with step 6.
1.
2.
Open the Networks menu in the Definitions tab.
In the Name entry field enter a distinct Name.
Allowed characters are: Letters of the alphabet, digits from 0 to
9, hyphen, space, and underscore characters. The name must be
fewer than 39 characters long.
3.
Now enter the IP Address of the NTP Server.
47
Using the Security System
4.
In the Subnet Mask entry field, enter the network mask
255.255.255.255.
5.
Now confirm your settings by clicking on the Add button.
WebAdmin will now check your entries for semantic validity.
Once accepted, the new network will appear in the network
table.
6.
Open the Settings menu in the System tab.
7.
In the Time Settings window make the following settings in the
given order:
Time Zone: Now select the time zone.
Use NTP Server: Select the NTP Server here.
The system clock of the Internet Security system will be synchronized
with the external NTP server every hour.
SSH (Shell Access) Settings
Secure Shell (SSH) is a textbased
access
mode
for
the
security system intended only
for advanced administrators. In
order to access this shell, you
will need an SSH Client, which
comes standard with most Linux distributions. For MS-Windows, we
recommend Putty as SSH Client. Access through SSH is encrypted,
and cannot be read by eavesdroppers.
The Shell Access function is enabled by default, once you have
entered a password for the configuration through the Astaro
Configuration
window.
48
Manager
in
the
Setting
System
Passwords
Using the Security System
If you wish to access the security system through SSH, the SSH
Status light must be enabled (status light shows green).
The SSH protocol uses name resolution (valid name server) if no
valid name servers are found, SSH access attempts will time out. The
time-out takes about a minute. During which time the connection
seems to be frozen or failed. Once the time-out has expired, the connection process continues without further delay.
You must also add the networks allowed to access the SSH service in
the Allowed Networks selection field. In order to ensure a seamless
installation process, the Allowed networks field contains the Any
option by default, this means that any computer can access the SSH
service. Networks can be defined in the Definitions/Networks
menu.
Security Note:
By default, anyone has access to the SSH service. The Allowed
Networks field contains the Any option. For increased security,
we recommend that access to the SSH service be limited. All
other networks should be removed!
We recommend that the SSH service be disabled when not in active
use.
Password and Factory Reset
The Password Reset function
allows you to set new passwords for the Security system.
If you log in to the WebAdmin
configuration tool for the first
time after this action, the Setting System Passwords window will
be displayed. This allows you to set optional passwords, such as the
Astaro Configuration Manager Password. Halt System will shut down
49
Using the Security System
the Security system. After the restart, the Setting System Passwords window will be displayed at first.
The Factory Reset function resets all configuration settings and options to their original state. All data entered after the initial installation will be deleted, including the HTTP Proxy Cache, the entire EMail Queue, Accounting and Reporting data, passwords, and
uninstalled Up2Dates.
The software version will not change. That is, all System Up2Dates
and Pattern Up2Dates that have been installed will be retained.
5.1.2.
Licensing
Some of the functions of the
security system, including the
Up2Date
Service,
High
Availability (HA), Surf Protection,
and
the
Virus
Protection
Support
service
from the Astaro partners, can
only be used with a valid
License Key. You can obtain
detailed
licensing
information
and
the
about
corres-
ponding licence keys at any certified Astaro Partner, or from Astaro:
salesus@astaro.com (America’s) and sales@astaro.com (Europe,
Asia Pacific and Africa).
First you need the Activation Key. With this Activation Key you
enable the License Key in MyAstaro. This allows you to select the
licensing period of the Internet security system yourself. You can thus
first install the software and then register your licence in the licence
portal - only from this moment of time on, starts the time period for
the acquired options.
50
Using the Security System
Note:
The Activation Keys cannot be used directly in the WebAdmin
configuration tool. Please register at MyAstaro first.
Creating an User Account:
1.
Open your browser and go to the site https://my.astaro.com.
2.
Log in under MyAstaro.
What is your e-mail address?
The e-mail address is used for the authentication. As new
customer enter the e-mail address into this entry field.
If you have already used the Registration Portal for Astaro
Security Linux V4, enter the e-mail address that you have used
for this registration into the entry field. If you don’t remember
the e-mail address that you used, you can request it under the
Returning Registration Portal users dialogue. You’ll need
your Username and the Password.
Do you have a MyAstaro password?
If you log in for the first time under MyAstaro, click on the No, I
am a new user check box. If you are already a user of
MyAstaro, enter the password into the Yes, my password is
entry field.
Then click on the Submit button.
3.
Create a new MyAstaro Account.
E-Mail Address: You can correct your address in this entry field.
Password: Enter your desired password here.
First Name: Enter your first name here.
Last Name: Enter your last name here.
Then click on the Register button.
51
Using the Security System
If the registration was successful, the page with the message
Congratulations, you have created your MyAstaro account
will be displayed. Moreover, you receive a confirmation by email.
Now you can download different versions of the Internet security
system under MyAstaro and execute the following actions for
your license:
1. Convert a Version 4 license to a Version 5 license
2. Register purchased Version 5 Activation Keys
3. Add options to your registered license
4. Download a free Home User license
5. Download a 30 days test version with additional features
Licensing the Internet security system:
In order to license the Internet security system, you need a valid
license file on the local host, so that you can import it to the Internet
security system through the WebAdmin configuration tool.
1.
Open the Licensing menu in the System tab.
2.
In the Upload License File entry field, click on the Browse
button.
3.
From the Select File dialogue, select the license file and click on
the Open button.
4.
Click on the Start button.
The system will require between 30 and 60 seconds to generate the
system. After successful registration, the License Information window will contain the details of your license.
52
Using the Security System
Licensing Information
After successful registration of the Internet security system, the
License Information window will show the details of your license.
Licensed Users (IPs)
The functions in this window are used for licenses that do not allow
for an unlimited number of users (IP-addresses).
View current User (IP) Listing: Clicking on the Show button
opens a table that lists all current users through their respective IPaddress.
Reset User (IPs) Listing: If you wish to reconfigure the internal
network, you can reset the user table by this action. Then there is a
reboot - the system will shut down completely and reboot.
This action is enabled by clicking on the Start button.
53
Using the Security System
5.1.3.
Up2Date Service
The Up2Date Service makes it
easy
to
keep
your
security
system software updated: New
virus
definitions,
system
patches, and security features
will be installed to your current
system.
All Up2Date data are digitally
signed and encrypted, and are
transferred over a secure channel. Only Astaro is entitled to create and digitally sign new Up2Dates
packages. Any unsigned or forged Up2Date packages are rejected
and deleted.
Astaro maintains a number of servers for both System Up2Date and
Pattern Up2Date that are dialed in the given sequence. If the first
Up2Date server is not available, the system will automatically query
the next system or pattern Up2Dates in the list.
Important note:
In order to download updates, the Up2Date Service makes a TCP
connection to the update server on port 443. The security system will
permit this connection without any adjustment. If there is another
security system in place upstream, you must allow the communication via the port 443 TCP to the update servers.
Note:
When using the High Availability (HA) system, please note the
special functions of System Up2Date.
54
Using the Security System
System Up2Date
The System Up2Date function allows you to import system patches
and new security features into your Internet security system. The
Up2Date packages can be downloaded either manually over an
encrypted connection or automatically from the Update Server. If you
don't have an Internet connection, you can also import Up2Date
packages from a local volume.
Newly imported Up2Date packages are presented with their respective
version number and file name in the Unapplied Up2Dates table.
These Up2Date packages have not been installed yet!
In order to get further information, touch the blue info button with
the cursor. If the info button is highlighted red, there will be an
automatic restart of the Security system after the installation of the
System Up2Date package.
Note:
If you are using the High Availability (HA) system, please note the
special notes for the import and installation of the System
Up2Dates.
The HA system is described in chapter 5.1.10 on page 97.
Individual
Up2Date
packages
can
be
downloaded
from
http://download.astaro.com/ASL/up2date and saved on your
local computer.
55
Using the Security System
Manually downloading System Up2Dates:
1.
Open the Up2Date Service menu in the System tab.
2.
In the System Up2Date window, click the Start button under
Prefetch Up2Dates now.
The system will now check if
there are any new updates
on the Update server, and
will download any updates
found. Details on the Up2Date process can be found in
the Log Window, shown in
real-time (left-hand picture).
When the
appears,
DONE message
the
process
has
completed successfully.
The Unapplied Up2Dates table lists any updates that have been
downloaded but not yet installed!
If you are using the HA system, unapplied updates will be listed in
the Unapplied Up2Dates Master window.
Automatic download of System Up2Dates:
1.
2.
Open the Up2Date Service menu in the System tab.
Click the Enable button under Prefetch Up2Dates automatically.
3.
In the selection menu Interval, specify how often the security
system should contact the Up2Date Server to check for new
System Up2Dates.
The available choices are: every hour, every day, or once per
week.
56
Using the Security System
Newly imported Up2Date packages are presented with their respective
version number and file name in the Unapplied Up2Dates table.
Further information is available by clicking the Info button.
Note that the Unapplied Up2Dates in the table have not yet been
installed yet!
If you are using the HA system, unapplied updates will be listed in
the Unapplied Up2Dates Master window.
Loading System Up2Dates from a local disk:
The filename of an Up2Date update consists of the version number,
tar to signify it is an encrypted archive file, and the file extension
.gpg. Example: 3.033.tar.gpg. Up2Date packages can be downloaded
from the ftp.astaro.com FTP server.
1.
Open the Up2Date Service menu in the System tab.
2.
In the System Up2Date window, click on the Browse button
next to Import from File.
3.
In the File Upload window, choose the Up2Date packages you
would like to load and click on the Open button.
Important note:
When using Microsoft Windows, make sure not to use a UNC
Path. Instead, choose the updates by using the Look in option.
4.
In the System Up2Date window, next to Import from File,
click Start.
Successfully loaded updates will appear in the Unapplied
Up2Dates window with the version number and the file name.
Further information is available by clicking the Info button.
Note that the Unapplied Up2Dates in the table have not yet been
installed yet!
57
Using the Security System
If you are using the HA system, unapplied updates will be listed
in the Unapplied Up2Dates Master window.
5.
Repeat steps 2 through 4 until all Up2Date packages have been
imported.
Installing System Up2Dates without the HA Solution:
1.
2.
Open the Up2Date Service menu in the System tab.
In the Unapplied Up2Dates table, choose the Up2Date updates
to install.
Note:
If more than one System Up2Date file is listed in the table,
start the highest version. The smaller versions will be installed
automatically.
3.
In the Actions column, click Install.
The progress of the Up2Date installation on system 1 will be
displayed in real time in the Log Window. When the DONE
message appears, the process has completed successfully.
Installing System Up2Date with the HA solution:
1.
Open the Up2Date Service menu in the System tab.
2.
In the Unapplied Up2Dates Master table, choose the Up2Date
updates to install.
Note:
If more than one System Up2Date file is listed, start with the
smallest version. Only one package can be installed with the
HA system.
4.
58
In the Actions column, click Install.
Using the Security System
The progress of the Up2Date installation on system 1 will be
displayed in real time in the Log Window. When the DONE
message appears, the process has completed successfully.
Then the installation automatiscally starts on system 2. During
this process, the Up2Date package and the message Polled by
slave will be displayed in the Unapplied Up2Dates Slave
table.
The table will show the message No locally stored Up2Date
packages available when the installation on system 2 has
completed successfully.
5.
If the Unapplied Up2Dates Master table lists more unapplied
updates, repeat steps 2 and 3 until all updates have been
installed.
The HA system is fully updated when the Unapplied Up2Dates
Master table shows the message No locally stored Up2Date
packages available and if both systems display the same
version number.
Pattern Up2Date
The Pattern Up2Date function
updates the virus patterns for
the security system’s integrated
virus scanner and the Intrusion
Protection System (IPS) with
IPS attack signatures. You can
choose
to
manually
update
or
signatures
automatically
at
certain intervals.
The Latest Pattern Up2Dates table shows the date of the most
recently installed Pattern Up2Date. Virus Protection Patterns and
Intrusion Protection attack signatures will be listed separately.
59
Using the Security System
Manual Pattern Up2Date:
1.
Open the Up2Date Service menu in the System tab.
2.
In the Pattern Up2Date window, click the Start button under
Update now.
The system checks now, whether new Pattern Up2Date packages are
available on the Update Server, downloads and installs them to the
Internet security system. Details on the complete Up2Date process
can be found in the Log Window, shown in real-time. When the
DONE message appears, the process has completed successfully.
The Installed Pattern Date will be updated when you click the
Up2Date Service under the System tab, or when you next open this
menu.
When using the High Availability (HA) solution, the virus scanner
on system 2 will be automatically synchronized with system 1.
Automatic Pattern Up2Date:
1.
Open the Up2Date Service menu in the System tab.
2.
Click the Enable button under Update automatically.
3.
In the selection menu Interval, specify how often the security
system should contact the Up2Date Server to check for new
Pattern Up2Dates.
The available choices are: every hour, every day, or once per
week.
Security Note:
Choose the hourly update option to ensure that your system is always up to date.
60
Using the Security System
The automatic Pattern Up2Date is now activated. The Security
system will contact the Up2Date Server at regular intervals and
check
for
new
Pattern
Up2Dates.
Whenever
new
Pattern
Up2Dates are installed, the administrator will be sent an e-mail
containing a list of the newest virus signatures.
When using the High Availability (HA) solution, the virus scanner
on system 2 will be automatically synchronized with system 1.
61
Using the Security System
5.1.4.
Backup
The Backup function allows you
to save the settings of your
Security system to a file on a
local disk.
This backup file allows you to
install a known-good configuration on a new or misconfigured
security system. This is especially useful in case of hardware
failure, as it means replacement
systems can be up and running
within minutes.
Attention:
Version 5.0 of the security system can only load backups from
version 4.021 or higher.
Install the License Key in the Licensing menu before loading the
backup. Without the appropriate license, the system will only support
three network cards – under certain circumstances, this can lead to
WebAdmin not being reachable.
62
Using the Security System
Note:
After every system change, be sure to make a backup. This will
ensure that the most current security system settings are always
available. Make sure that backups are kept securely, as the backup
contains all of the configuration options, including certificates and
keys.
After generating a backup file, you should always check it for
readability. It is also a good idea to use an external MD5 program to
generate checksums: this will allow you to check the integrity of the
backup later.
Restore a Backup
This window allows you to install the backup file of the configuration.
Loading a Backup:
1.
Open the Backup menu in the System tab.
2.
In the Restore a Backup window next to the Upload Backup
File entry field, click on the Browse button.
3.
In the File Upload window, choose the Backup file, you would
like to load and click on the Open button.
Note:
When using Microsoft Windows, make sure not to use a UNC
Path for loading the backup. Select the Backup file with the help
of the Look in selection window.
4.
Click on the Start button.
If, during the generation of the backup file, the Encryption
function was enabled, the Enter Passphrase window will open.
5.
In the Passphrase field, enter the password.
63
Using the Security System
6.
Confirm your settings by clicking Start.
The security system will now load and check the backup file. If
the ckecksums are correct, you will now receive the Backup
Information.
7.
Check the Backup Information.
8.
To import the backed-up settings into the active system, click
the Start button.
When the message Backup has been restored successfully
appears, the process has completed successfully.
Create a Backup
This window allows you to create and archive a backup file of the
configuration of your Security system.
Manually Creating a Backup:
1.
Open the Backup menu in the System tab.
2.
In the Create a Backup window, in the Comment field, enter a
description of this backup.
When
restoring
system
backups,
this
description
will
be
displayed to help distinguish between different configurations.
Important note:
If the Encryption function has been enabled, the backup file
will be encrypted with either the DES or 3DES algorithms, and
can only be read or loaded using the correct password.
3.
To generate the backup file, click the Start button.
The system will now generate a backup file. When the message
Backup has been restored successfully appears, the process
has completed successfully.
4.
64
To copy the backup file to your local PC, click the Save button.
Using the Security System
5.
On the File download menu, choose the Save file to disk and
click the OK button.
6.
Choose a descriptive file name on the Safe file as menu.
The security system will automatically produce file names,
consisting of backup, date and time:
backup_yyyymmdd_hhmmss.abf (astaro-backup-file).
7.
Check the generated backup file for readability by importing it
back into WebAdmin and clicking on the Start button.
The security system will now load and check the backup file. If
the ckecksums are correct, you will now receive the Backup
Information.
8.
Abort the restore process by opening a different menu within the
tab.
Attention:
After each system change, create a new backup file. If you load
a new backup file and if, for example, you have changed the IP
address or forgotten the password, you might not be able to
access the newly configured system.
65
Using the Security System
Advanced
Encryption: The backup file contains all configuration settings as well
as the respective certificates and keys. The Encryption function
allows you, to encrypt the file using DES or 3DES.
Encryption of e-mail Backup Files:
1.
Open the Backup menu in the System tab.
2.
Scroll to the Advanced window.
3.
Enable the Encryption function by clicking on the Enable
button.
The Encryption function is enabled, when the status light shows
green.
4.
In the Passphrase entry field, enter the password.
Security Note:
With passwords with up to seven characters, the Backup
file will be encrypted with DES and from eight characters
on with 3DES.
5.
To confirm, enter the password again into the Confirmation
entry field.
6.
Click the Save button to save these settings.
All Backup files that have been created manually or automatically by
the system, will now be encrypted with the defined password.
Important note:
A backup file that has been encrypted with Encryption can only be
loaded to the system with the password that was used for the
creation of the Backup.
66
Using the Security System
Send Backups by E-Mail: The Security system can also send you
automatically created backup files by e-mail, so that you don’t have
to remember to save the settings of your Internet security system
manually on a data carrier. Then the file is e-mailed to the entered email address. These e-mailed files are about 100 kilobytes long.
Generating an E-Mail Backup File generieren:
1.
Open the Backup menu in the System tab.
2.
In the Advanced window enable the Send Backups by E-Mail
function by clicking on the Enable button.
The Backups by E-Mails function is enabled, if the status light
shows green.
Important note:
If the Encryption function has been enabled, the backup file
will be encrypted with either the DES or 3DES algorithms, and
can only be read or loaded using the correct password.
3.
Use the Interval drop-down menu to define how often backups
should be made.
The available choices are: Daily, weekly, and monthly.
4.
In the E-Mail to field, enter the e-mail addresses, which should
receive the backup files in regular intervals.
5.
Click the Add button next to the E-Mail to entry field, to add
this address to the ordered list.
If you would like to add more addresses, repeat step 5.
6.
If you wish to generate and send a backup file immediately, click
the Start button next to Send backup now.
7.
Check the generated files for readability by importing the
respective backup file and clicking on the Start button.
67
Using the Security System
The security system will now load and check the backup file. If
the ckecksums are correct, you will now receive the Backup
Information.
8.
Abort the restore process by opening a different menu within the
tab.
Editing E-Mail Addresses:
Please see chapter 4.3.4 on page 39 for a description of how to use
the ordered list.
5.1.5.
SNMP Access
The Simple Network Management Protocol (SNMP) monitors and manages the local network. SNMP allows the administrator to make quick queries
about the condition of the network devices, such as the number and
configuration of the network interfaces, the forwarded traffic, the
current processes and hard disk utilization. Next to the current state,
tendencies and time rows are interesting. They give a detailed insight
into the functions of a network – the history can be monitored and
remedied before turning into a real problem.
Configure the access rights to the SNMP service in the SNMP Access
window. The users of the configured networks can then conduct
queries about the SNMP server on the Security system with their read
only rights.
Security Note:
The SNMP data traffic (Protocol version 2) between the Security
system and the network is not encrypted.
68
Using the Security System
Authorizing access to the SNMP server:
1.
Enable SNMP Access by clicking the Enable button.
2.
From the Allowed Networks selection field, select the networks
that you wish to allow for accessing the SNMP server.
3.
Enter the Community String in this entry window.
4.
Save your configuration by clicking Save.
5.1.6.
Remote Syslog Server
This function allows you
to forward log messages
from the Security system
to other hosts. This is
especially useful for networks using a log host to
collect logging informa-
tion from a number of different hosts. By default, this function is
disabled. A Logging Daemon, compatible with Syslog protocol must be
running on the selected host.
Attention:
In the System/Remote Syslog Server menu, do not select one of
the security system’s interfaces (such as eth0) as the destination
address (host).
Host: Enter the host, which should receive logging information in the
drop-down menu. When a host has been selected, log forwarding is
enabled immediately: no further messages are displayed.
In order to select a logging host (i.e., a network with netmask
255.255.255.255) you will first have to define it in the Definitions/Networks menu. The definition of networks is covered in
greater detail in chapter 5.2 on page 103.
69
Using the Security System
Service: The Syslog protocol is set by default. You can also use this
drop-down menu to configure the service ( port) that should be used
on the remote server.
Logs: This selection field allows you to select log files that should be
delivered to the Remote Host.
70
Using the Security System
5.1.7.
User Authentication
The security system supports User Authentication using the
SOCKSv5, SMTP, and HTTP proxy services and can control which
users are allowed to use which services. User accounts can be defined
on the security system, through the Definitions/ Users menu. Or on
an external user database. Supported external databases include
RADIUS, SAM (Windows NT/Windows 2000/XP-Server), Microsoft
Active Directory and OpenLDAP. If an external user database is
already present on the network, you can use it instead of having to
re-enter user accounts on the security system itself.
User Authentication requires users to identify themselves before using
network services. This allows for user-based access control and
accounting rather than an IP-based access control. This allows for
user-based Accounting in the HTTP-Proxy access protocol.
Proxy Service and Authentication Methods
The SOCKSv5, SMTP, and HTTP services can be configured to allow
or disallow clients based on IP address or on username and password
combinations. In order to use User Authentication, you must select
at least one database against which the security system should
authenticate users. If user authentication is enabled and no database
is selected, the proxy service cannot be used.
The security system supports user authentication against ...
•
A RADIUS Server
•
An NT SAM user list
•
An LDAP Server
•
An internal database defined in WebAdmin
The four user databases can be checked one after the other.
71
Using the Security System
5.1.7.1.
RADIUS
RADIUS stands for Remote Authentication Dial In User Service
and is a protocol for allowing network devices (e.g., routers) to
authenticate users against a central database. In addition to user
information, RADIUS can store technical information used by network
devices. Such as protocols supported, IP addresses, telephone
numbers, routing information, and so on. Together this information
constitutes a user profile that is stored in a file or database on the
RADIUS server.
In addition to authenticating dial-up users, RADIUS can be used as a
generic authentication protocol.
The RADIUS protocol is very flexible, and servers are available for
most operating systems, including Microsoft Windows NT/2000. The
RADIUS implementation on this security system allows you to
configure access rights on the basis of proxies and users.
Before you can use RADIUS authentication, you must have a
functioning RADIUS server on the network. As passwords are
transferred in clear text (unencrypted), we strongly recommend that
the RADIUS server be inside the network protected by the security
system, and that the security system and server be on the same
switch.
The following section details the setting up Microsoft IAS (RADIUS
Server for MS Windows NT and 2000). If you use a different server,
you will need the following information to enable the operation of the
security system together with the user authentication.
The authentication request comprises three set fields:
•
Username
•
Password in clear text (PAP)
•
Type of proxy (the string http, smtp or socks) in the NASIdentifier field
72
Using the Security System
Your RADIUS server should use this information to determine whether
or not access should be granted, and should send back a properly
formatted reply.
Configuring Microsoft’s IAS RADIUS Server:
IAS is a part of all versions of Microsoft Windows 2000 Server, but is
generally not installed by default. For Microsoft Windows NT4, IAS is
a part of the NT4 Option Pack and is available without charge. The
MS Windows NT4 IAS has fewer features than the 2000 version, but is
nevertheless sufficient for user authentication with the security
system.
1.
Check that the IAS service is installed. If it is not, install it now.
2.
Create a user group for every proxy to be used.
Tip:
Name the group according to the proxy to be used. For
example, name the group for the HTTP Proxy HTTP Proxy
Users.
3.
For each group, add the users who should be allowed to use this
proxy service.
4.
Make sure that the user flag Allow dial-in access to the network is set for every user in these groups.
You can find this setting in the user properties dialog box. MS
Windows NT/2000 needs this flag to answer RADIUS inquiries.
5.
Open the administration program for the IAS service.
6.
Add a client. This requires the following information.
Client Name: Enter the DNS name of your security system
here.
Protocol: Choose RADIUS.
IP Address of the Client: Enter the internal IP address of the
security system.
73
Using the Security System
Client Vendor: Choose RADIUS Standard.
Shared Secret: Enter a password here. You will need this
password again when configuring the RADIUS server with
WebAdmin.
Security Note:
For the Shared Secret only passwords consisting of
alphanumeric, minus (-), and period (.) characters are
allowed. Other characters, for example %!#_{} are not
allowed.
7.
Now open the RAS rules menu.
A standard rule is listed here. If you intend to use IAS only with
the security system, you can delete this entry.
For every proxy, enter a rule. Choose a descriptive name, such
as HTTP access.
Add two conditions:
1. Condition 1: The NAS Identifier field must correspond to a
string from the following table.
Proxytyp
NAS Identifier String
HTTP
http
SOCKS
socks
SMTP
smtp
WebAdmin Access
webadmin
Surf Protection
“Profile name”
PPTP
No identifier
2. Condition: The Windows group of the user must match the
group established in step 2.
Access is granted only when both conditions are met.
74
Using the Security System
8.
Edit the profile for the rule so that unencrypted authentication
(PAP) is allowed.
Leave the other values unchanged.
9.
Open the WebAdmin configuration tool and open the User
Authentication menu in the System tab.
10. In the RADIUS Server Settings window, click the Enable
button next to Status (the status light will show green).
Address
or
Hostname:
Enter the IP address or the
host name of the RADIUS
server.
Shared Secret: Enter the Shared Secret from step 6.
11. Click the Save button to save these settings.
12. In the Proxies tab, open the menu corresponding to the proxy
service you wish to use.
13. If User Authentication is not enabled (red status light), click
the Enable button.
Authentication Methods: Choose RADIUS from the selection
field.
14. Now confirm your settings by clicking on the Add button.
The user authentication using RADIUS is now active.
The IAS service will log every access attempt in the Microsoft
Windows NT/2000 Event Log.
In order to prevent the Windows Event Log from overflowing, the
security system stores caches RADIUS access information for five
minutes. This may mean that changes in the RADIUS database will
not be reflected at the security system for a few minutes.
75
Using the Security System
Attention:
The security system sends queries on UDP port 1812.
5.1.7.2.
SAM – NT/2000/XP
This authentication method uses an MS Windows NT/2000 Domain
Controller or standalone server. Many businesses already use MS
Windows NT/2000 networks based on ActiveDirectory.
The advantage of SAM is that it is very easy to configure if the
network already has a Primary Domain Controller (PDC) or if a
server with a user database is running.
The drawback, however, is that this system does not distinguish
between different user groups. You can either allow all users in an
SAM database access to a proxy or none of them.
Configuring SAM – NT/2000/XP:
In order to use this authentication method, you will need to
have a Microsoft Windows NT or
2000 server on your network
that contains the user information. This can be either a
Primary Domain Controller (PDC) or a standalone server.
Note that Windows servers have a NetBIOS name (the NT/2000
server name) as well as an IP address.
1.
In the System tab, open the User Authentication menu.
2.
In the SAM (NT/2000/XP) Server Settings window, click the
Enable button next to Status.
76
Using the Security System
PDC Name: Enter the name of the Domain Controller in this
entry field.
Since, beginning with Windows 2000, these names are also
official DNS names, only names consisting of alphanumeric,
minus (-), and period (.) characters are allowed.
Other characters, for example %!#_{} are not allowed.
PDC Address: Enter the IP address of the Domain Controller.
BDC Name: If you have a Backup Domain Controller, enter its
name in this entry field. If you do not use a BDC, enter the name
of the PDC here.
BDC Address: If you have a Backup Domain Controllers, enter
its IP address here. If you do not use a BDC, enter the name of
the PDC here.
NT4 Domain: Enter the name of your MS Windows NT/ 2000Domain.
Allowed characters are: Letters of the alphabet, digits from 0 to
9, hyphen, and underscore characters.
Note:
This is not the Internet domain, as in Company.com, but rather
a simple designator, e.g., Intranet. If you are using a standalone server rather than a Domain Controller, enter its NETBIOS
name here. This corresponds to the PDC Name entry.
3.
Click the Save button to save these settings.
Security Note:
For the Shared Secret only passwords consisting of
alphanumeric, minus (-), and period (.) characters are
allowed. Other characters, for example %!#_{} are not
allowed.
77
Using the Security System
Security Note:
If you use SAM authentication, make sure to disable the Guest
account on your Windows domain. Otherwise all username/
password combinations will be accepted as valid.
5.1.7.3.
LDAP Server
LDAP, the Lightweight Directory Access Protocol defines the way
in
which
clients
communicate
with
X.500-conforming
directory
services. The protocol thus specifies the type of access to such a
directory service.
The security system uses the LDAP protocol to authenticate users for
several of its services. The security system allows or denies access on
the basis of certain attributes or group memberships established on
the LDAP server.
This system supports the Microsoft Active Directory and Novell
eDirectory LDAP servers as well as those based on the Open Source
OpenLDAP software.
Microsoft Active Directory is an indexing service designed especially for Windows NT/2000 networks, and allows the central management and organization of network resources. It allows users to access
system resources after a single sign on to a central server, and offers
administrators centrally organized management of users, regardless
of network topology or protocols used.
In order to use this directory service, you will need an MS Windows
NT/2000 Domain Controller.
Novell eDirectory – Novell Directory Service 8 - is an X.500-based
index service designed to manage users, access rights, and other
network resources. eDirectory is available for Netware versions 5 and
higher, MS Windows NT/2000, Linux, and Solaris.
The OpenLDAP Foundation, the group which manages the OpenLDAP open source project, has released the Stand-Alone LDAP
78
Using the Security System
server, called SLAPD. OpenLDAP can also be used to build a
networked directory service with various other LDAP servers: For
instance, the iPlanet Directory Server from Sun Microsystems is
based on OpenLDAP code and fully compatible.
User Authentication
LDAP uses the Distinguished Name (DN) of a user to identify him
or her. This name must be unique within the directory.
Microsoft Active Directory (AD) and Novell eDirectory (NDS8)
give every object a defined DN. This DN identifies the object uniquely
in the AD index or NDS tree. This DN is composed of the Common
Name (CN) and Domain Component (DC).
Example: CN=Administrator, CN=Users, DC=example, DC=com
MS Active Directory also allows for user authentication by User
Principal Name (UPN). This name consists of the login name and
DNS name of the domain.
Example: admin@example.com
OpenLDAP simply uses the Common Name (CN) to identify users.
Please make certain that every user has a unique CN.
Security Note:
User authentication with a stand-alone LDAP server involves
sending passwords in clear text over the network. As these
passwords are not encrypted, an attacker with access to the
network may be able to intercept them.
Note:
User authentication with an LDAP Server requires that the DNS
Proxy on the Proxies/DNS menu be enabled.
79
Using the Security System
Configuring the Microsoft Active Directory Server:
Make sure that there is a user configured on your LDAP server to have
full read privileges for the directory. This will be the query user.
Security Note:
Make sure that the user has only read privileges.
Microsoft Active Directory (AD) can grant privileges on the basis
of group memberships, or on the basis of particular user attributes. In
most cases, it is easier to use the Member Of query type to
authenticate by group.
The Directory can be extended by self-defined attributes. If you wish
to authenticate on the basis of particular User Attributes, every user
account in the directory must be edited to define access rights. This is
done by setting a particular attribute for each user which either grants
or denies access to a service.
The
following
example
illus-
trates the configuration for a
hypothetical
small
company
example.com:
The user John Smith is in the
Trainees directory.
DN: cn=john smith,
ou=trainees, dc=example,
dc=com.
LogonName:
smith@example.com
This user can use his LogonName and password to log on to services
like the SOCKS Proxy. The security system checks the user’s DN and
password.
If
there
is
only
one
DN
that
corresponds
to
smith@example.com, and if the supplied password is valid, the user
will be allowed to use the SOCKS proxy.
80
Using the Security System
If you wish to use Group Membership to control access rights,
complete the following steps to configure the Microsoft Active
Directory:
Step 1 – Creating a Security Group:
1.
In the Microsoft Management Console, click the domain with
the right mouse button.
Example: Domain example.com
2.
With the left mouse button, click New and then Group.
A new window will open labeled New Object - Group.
3.
Enter a unique name for the group in the Group name field.
Example: socks_users for the SOCKS Proxy
4.
Under Group type select Security.
5.
Save your settings by clicking OK.
You
have
now
created
a
new
Security
Group
named
socks_users.
Step 2 – Adding Users to the Group:
1.
In the directory, right-click the username.
Example: John Smith in the Trainees directory.
2.
Left click the Properties button.
A window named Properties will open.
3.
In the Properties window, select Member Of tab.
4.
Click Add to add the new group.
The Select Groups window will open.
5.
Now choose the Security Group you wish to add the user to.
Example: socks_users
81
Using the Security System
6.
Save your changes by clicking OK.
The new Security Group will be added in the Member Of
window.
7.
Save your settings by clicking OK.
Now execute the settings on the Internet security system. The
settings in the configuration tool WebAdmin are explained on page
87.
Microsoft Active Directory, self defined attributes:
User authentication with Microsoft Active Directory can also use user
attributes to assign access rights. For large organizations, however,
this can be time-consuming to configure.
Note:
According to the LDAP standard, each user attribute must have an
associated object ID, or OID. Object ID numbers are designed to
be unique across the entire Internet; in order to manage this, the
Internet Assigned Numbers Authority (IANA) has been charged
with assigning OID prefixes to organizations. For example, the OID
prefix for Astaro AG is: 1.3.6.1.4.1.9789.
If your organization does not yet have an official OID space, you can
request
an
OID
prefix
from
the
IANA
at
www.iana.org.
Once you have an OID space, you should consider how best to use it
to describe your network structure. Remember that each user
attribute will require a unique OID.
In order to configure user attributes, the Microsoft Management
Console must be used to modify the Active Directory Schema. In
order to do this, you must first mark the schema as editable.
82
Using the Security System
Step 1 – Enable Editing of the Active Directory Schema:
1.
In the Microsoft Management Console, right-click Active
Directory Schema.
2.
Use the left mouse button to click Operations Master.
The Change Schema Master window will open.
3.
Check the option The Schema may be modified on this
Domain Controller.
4.
Save your changes by clicking OK.
The Active Directory Schema can now be edited.
Step 2 – Add New Attributes:
1.
Under Active Directory Schema, right click Attribute.
2.
Use the left mouse button to click New.
3.
In the Create New Attribute window, define the new
attribute.
Common Name: Enter a CN for this attribute.
LDAP Display Name: Give the new attribute a clear label. The
name of the service this attribute controls would be a good
choice.
Example: Socks.
Unique X500 Object ID: Enter the OID for this attribute in the
entry field.
Syntax: Chose Boolean.
Minimum: Leave this field blank.
Maximum: Leave this field blank.
4.
Save your settings by clicking OK.
83
Using the Security System
Step 3 – Allocate a Class for the Attribute:
1.
Under Active Directory Schema, left-click Classes.
2.
Right-click Users.
A window named User Properties will open.
3.
Click the Attributes tab and make the following settings.
Optional: Use the drop-down menu to select the attribute and
click Add.
4.
Save your settings by clicking OK.
5.
In the Microsoft Management Console, right-click Active
Directory Schema.
6.
With the left mouse button, click Reload the Schema.
Step 4 – Setting the Attribute for Users:
1.
In the ADSI Edit window, right-click the user to edit.
Example: John Smith in the Trainees directory.
2.
Left click the Properties button.
A window named Properties will open.
3.
In the Properties window, click the Attributes tab.
4.
Select which properties to view: Choose Both.
5.
Select a property to view: Choose the attribute to set.
Example: Socks.
Syntax: This value was set while creating the attribute and
cannot be changed.
From step 2, this should be. Boolean.
Edit Attribute: You can use this field to set the value of the
attribute. The possible values are TRUE and FALSE.
Value(s): The current value of the attribute is shown here.
84
Using the Security System
6.
Save your settings by clicking OK.
Now make the settings on the Internet security system. The settings
in the configuration tool WebAdmin are explained on page 87.
Configuring a Novell eDirectory Server:
Make sure that there is a user configured on your LDAP server to have
full read privileges for the directory. This will be the query user.
Security Note:
Make sure that the user has only read privileges.
In most cases, you should use the groupMembership query type
with Novell eDirectory (NDS8), as this allows an existing user
index to be easily extended for proxy rights.
The index can also be configured to use user-defined attributes, which
must be manually set for each user in the index. If you wish to
authenticate on the basis of particular User Attributes, every user
account in the directory must be edited to define access rights. This is
done by setting a particular attribute for each user which either grants
or denies access to a service.
You will need Novell ConsoleOne to configure the eDirectory Server.
The configuration and management of the Novell eDirectory server is
described in detail in the accompanying documentation. You can find
these documents at:
http://www.novell.com/documentation/lg/edir87/index.html
Then make the settings for the Internet security system. The settings
in the configuration tool WebAdmin are explained on page 87.
85
Using the Security System
Configuring the OpenLDAP Server:
Make sure that there is a user configured on your LDAP server to have
full read privileges for the directory. This will be the query user.
Security Note:
Make sure that the user has only read privileges.
With OpenLDAP, users are identified on the basis of their Common
Names (CN). Please make certain that every user has a unique CN.
Important note:
With the installation of the software alle existing data will be deleted
from the computer!
Because there are many different LDAP servers based on the
OpenLDAP code, it is impossible to describe them all here. For
further information, please consult the documentation accompanying
your LDAP server.
If you are using the SLAPD server from the OpenLDAP Foundation,
the current documentation is available at:
http//www.openldap.org.
86
Using the Security System
Configuring LDAP on your Security System:
Make sure that there is a
user configured on your
LDAP server to have full
read
privileges
for
the
directory. This will be the
query user.
You will need the Distinguished Name (DN) of
this user as well as the IP
address of your LDAP server in order to complete the configuration of
the security system.
Security Note:
Make sure that the user has only read privileges.
1.
In the System tab, open the User Authentication menu.
2.
In the LDAP Server Settings window, enable the system by
clicking Enable next to Status.
LDAP Type: Choose the type of LDAP server to use.
The available choices are: Microsoft Active Directory, Novell
eDirectory and OpenLDAP.
Unique User Attribute: This attribute defines how users should
be authenticated on the LDAP server. The attributes available
here depend on the type of LDAP server you are configuring. If
you wish to use a self-defined attribute for authentication, select
Selfdefined here.
With the Microsoft Active Directory server, you can also
choose to authenticate by User Principle Name (UPN) or
saMAccountName.
87
Using the Security System
The
Novell
eDirectory
and
OpenLDAP
servers
allow
authentication by the Common Name (CN), Surname (SN),
and Unique Identifier (UID) attributes.
Attribute Name: This entry field is only shown if
you have selected to authenticate
by
a
Selfde-
fined attribute from the
Unique
User
Attribute
drop-down menu.
Enter the attribute to use for authentication here.
IP Address: Enter the IP address of the LDAP server.
TCP Port: Enter the TCP port of the LDAP service. By default,
this is set to 389 (the standard port for LDAP).
Bind DN: The value to enter here depends on the type of LDAP
server you are using.
1. Microsoft Active Directory
Microsoft Active Directory can use either the User Principal
Name (UPN) or the full Distinguished Name (DN) of the
user.
Examples:
UPN: admin@example.com
DN: cn=administrator, cn=users, dc=example, dc=com
2. Novell eDirectory
Enter the full Distinguished Name (DN) of the user.
Example:
DN: cn=administrator, o=our_organisation
3. OpenLDAP
OpenLDAP and OpenLDAP-conforming servers can only use the
Distinguished Name (DN) of users.
Base DN: Enter the object name to be used as the basis for all
client actions.
88
Using the Security System
Examples:
For MS Active Directory: dc=example, dc=com
For Novel eDirectory: o=our_organisation
7.
Enter the password in the Password entry field. This password
should also be used for the Administration of the Stand-aloneLDAP-Server.
Security Note:
Use a secure password! Your name spelled backwards is,
for example, not a secure password – while something like
xfT35$4 would be.
8.
Click the Save button to save these settings.
Security Note:
As long as the LDAP authentication by attribute
function is disabled, all users who are listed in the directory
with a unique DN and a valid password can use the HTTP,
SMTP and SOCKS proxies, and can also access the
WebAdmin tool.
89
Using the Security System
Advanced Authentication with LDAP:
1.
Enable the LDAP authentication by attribute function by
clicking Enable next to Status.
2.
Use the Service drop-down menu to select a service.
The available services are: HTTP, SMTP, SOCKS and WebAdmin.
3.
In the Attribute Name field, enter the name of the attribute.
If you are using authentication using the MemberOf property on
a Microsoft Active Directory Server, this should be the name
of the Security Group to use.
Example: socks_users.
4.
In the Attribute Value field, enter the DN for the attribute. The
attribute value is the DN.
Microsoft Active Directory
displays the DN of attributes
in the Management Console, under ADSI Edit:
Here, under the Base DN
(example: dc=example, dc=
com), find the attribute name
(example: socks _users) and
right-click
labeled
it.
A
window
CN=socks_users
Properties will open.
Use the Select which properties to view drop-down menu to
choose Both, and in the Select a property to view drop-down
menu, choose distinguishedName. The DN for this attribute
will be shown in Value(s).
5.
90
Click the Save button to save these settings.
Using the Security System
Every
member
defined
as
a
MemberOf
the
security
group
socks_users will be allowed to use this service.
5.1.8.
WebAdmin Settings
Configure the access to the WebAdmin configuration tool in this
menu.
General Settings
Language: In this dropdown menu you can determine the language.
Timeout (seconds): In this entry field enter the intervals in seconds, in which WebAdmin automatically logs you out, if there are no
actions. By default, the system is set to 300 seconds after the installation. The smallest possible interval amounts to 60 seconds.
Click the Save button to save these settings.
If you close your browser with an open WebAdmin session without
closing WebAdmin through Exit, the last session reamins active until
the end of the time-out.
TCP Port: If you want to use the standard port 443 for the HTTPS
service for another purpose (such as a deviation with DNAT), you
must enter another TCP Port for the WebAdmin Interface here.
Possible values are 1024-65535, while certain ports are reserved for
other services. In order to address WebAdmin after a modification,
you must separately link the port through a colon to the IP-address of
the Internet security system,
e.g.: https://192.168.0.1 :1443.
91
Using the Security System
Access and Authentication
Allowed Networks: Add
those
networks
selection
authorised
field
to
the
that
are
to
access
WebAdmin. As with SSH,
Any is entered here for a
smooth installation. In this
case and if the password is
available, WebAdmin can be accessed from everywhere.
Security Note:
As soon as you can limit the access to the Internet security
administration (for example your IP address in the local network),
replace the Any entry in the Allowed Networks selection field
through a smaller network.
The safest solution is, if only one administrator PC has access to the
Internet security system through HTTPS.
Networks can be defined in the Definitions/Networks menu.
Authentication Methods: Select the authentication method in the
selection field. In order to give you access to the Internet security
system
through
the
configurations
tool
WebAdmin
after
the
installation, the authentication method Local Users has already been
defined here and the respective User hase been entered in the
Allowed Users selection menu.
Further available authentication methods are NT/2000/XP Server,
RADIUS Database and LDAP Server.
Local Users are administered in the Definitions/Users menu.
Allowed Users: By default this is set to the user admin.
Local users are defined in the Definitions/ Users menu.
92
Using the Security System
Block Password Guessing
This function can be used
to limit the number of attempts to log in to the
WebAdmin
configuration
tool. After a specific number of attempts, the access from this IP address will be denied for a
given time span.
Configuring the blocking protection for Login attempts:
1.
Configure the maximum allowable number of attempts in the
After failed Attempts drop-down menu.
2.
Enter the time span for the blocking protection in the Block IP
for Period entry field.
3.
Save your changes by clicking Save.
Now, the blocking protection is enabled. The Never block Networks
window, allows you to exclude networks or hosts from the blocking
protection.
93
Using the Security System
5.1.9.
WebAdmin Site Certificate
Encryption systems are an important part of many modern security
systems. They are used, for example, when transmitting confidential
information over Virtual Private Networks (in chapter 0 on page
254), in user authentication and Up2Date Service or, to securely
administer the security system over the network.
Certificates and Certificate Authorities (CA) are an essential part of
modern cryptographic protocols, and help close the gaps left open by
other systems. Public Key Algorithms offer a particularly elegant
form of encryption. They do, however, presuppose that the public
keys of all communications partners are known.
At this point, a third, trusted party is used to ensure the validity of
public keys. The third party issues certificates guaranteeing the
authenticity of these keys: this third party is called a Certificate
Authority (CA). A certificate is a record in a standardized format
with the owner’s most important data - his name, and his public key and is signed with the private key of the CA. The format for these
certificates is defined in the X.509 standard.
In a certificate, the CA certifies, with its own signature, that the
public key belongs to the person (or entity) it says it does. As the
certificate contains information such as the name of the owner,
duration of validity, issuing authority, and the signature of the CA, it
can be seen as a kind of digital passport.
The WebAdmin Site Certificate menu allows you to
create two certificates: first
a CA certificate, which will
be installed in your browser,
and
second
the
server
certificate (signed by the CA
94
Using the Security System
certificate) which the system uses to authenticate itself to your
browser. These two certificates contain the company’s data and the
system’s hostname.
Creating a Certificate for WebAdmin:
1.
Under the System tab, open the WebAdmin Site Certificate
menu.
2.
In the Certificate Information menu, enter the appropriate
information for your firm.
Country: Choose your country from the drop-down menu.
State: Choose the state or region where you are.
City: Enter the company’s name.
Organization: Enter the company’s name.
Section: Enter the department.
E-Mail Address: Enter your e-mail address.
3.
In the field Firewall Hostname, enter the host name or IP
address of the firewall you use to access WebAdmin.
Example:
If
you
access
WebAdmin
through
the
URL
https://192.168.10.1, enter 192.168.10.1 here.
4.
Save your entries by clicking the Save button.
Installing a Certificate for WebAdmin:
1.
To install the CA Certificate in your browser, click Import
Certificate into Browser in the CA Certificate Installation
window
The next few steps depend on your browser. For example, with
Microsoft Internet Explorer, the File download dialog opens.
Save file to disk: This option allows you to save the certificate
to a local disk before installing it.
95
Using the Security System
Open the file from current position: This allows you to install
the certificate directly. The Certificate window will open. These
registers allow you to inspect the information contained in the
certificate before installing it.
5.
Click the OK button to start the process.
Note:
Due to system time differences and timezone offsets, the generated
certificate may not yet be valid. Many browsers wrongly report that
such certificates have expired, however this is not the case and any
generated certificates will become valid after a maximum of 12
hours.
96
Using the Security System
5.1.10. High Availability
The main cause of system failure is hardware failure, such as a failure
of the network card, hard disk, or processor. The High Availability
(HA) option allows you to use two systems with identical hardware in
parallel. The first system runs normally (master mode), while the
second runs in standby (slave) mode, monitoring the active system
over the data transfer link using the link beat. The standby system
also receives periodic updates over this link so that, in the case of
system
failure
on
the
primary,
it
can
take
over
operations
immediately.
Hardware and Software Requirements
•
The High Availability (HA) License
•
2 security systems with identical hardware
•
2 additional Ethernet interfaces (if you wish to use heartbeat
monitoring, both of these must support link-beat)
•
One Ethernet crossover cable
•
One serial interface cable (optional)
97
Using the Security System
Important note:
The hardware components, supported by the Internet security
system, e.g. for a monitoring through Heart-Beat-requests are listed
under http://docs.astaro.org in the Hardware Compatibility
List for Astaro Security Linux tab.
Installing the High Availability-System
Preparation:
1.
First install the software on both machines and configure the first
(active) system as described in chapter 3.2 on page 22.
Security Note:
If you install High Availability (HA) to a system updated
using Up2Date, please ensure that the standby system is
using the same version of the security solution as the
normal-mode system.
2.
Shut both systems down.
3.
Connect the firewall system 2 (standby) to the firewall system 1
(active) as in the graphic.
Configuring the Firewall System 1 (normal mode):
1.
Start system 1 as normal.
2.
In the System tab, open the High Availability menu.
3.
Enable the HA system by clicking Enable (under Status).
Device Name: Enter a descriptive name for the system here.
This name will be shown to allow you to know which system is
active at a given time. The name can be up to 11 characters
long.
98
Using the Security System
Device IP: Assign an IP-address from a Class-C-network to
each security system within the HA-device group. The IPs must
be within an address range and may only be used once within a
given device group. Example: The Device IP 10.0.0.1 is assigned
to the Internet security system 1 and the Device IP 10.0.0.2 to
security system 2.
Encryption Key: Enter a password here.
Security Note:
Use a secure password! Your name spelled backwards is,
for example, not a secure password – while something like
xfT35$4 would be.
Network Interface Card: Select a network card to be used for
the data transfer connection. When an interface is selected for
HA mode, it cannot be used in any of the other configuration
menus.
Important Note:
The network cards used for the connection must have the same
Sys ID (e.g., eth3) on both systems.
If you wish to use heartbeat monitoring, use this menu to
choose network cards on both the normal and standby systems
which support link beat.
Transfer Network: Enter the Network Address for the data
transfer connection here.
Note:
Note: The data transfer connection must use a Class C network
– that is, a network with mask 255.255.255.0. The bitmask
form cannot be used.
The data transfer network cannot be used for anything other
than data transfer.
99
Using the Security System
The entry fields contain suggestions generated by the system.
You do not need to accept the default values.
Serial Interface (optional): In addition to watching the data
connection, the standby system can monitor the active system
through the serial interface. No data is transferred over this
connection. Use the drop-down menu to select the appropriate
serial interface to use this option.
Note:
When you save the settings, according to the following
instructions, the system will shut down and reboot immediately.
4.
Click the Save button to save these settings.
The first system will shut down and reboot immediately. If you
have connected a keyboard to this machine, the Num Lock light
will flash.
When the system is in Hot Standby Mode, it will beep twice and
the LED display will stop blinking. Because system 2 is still
disabled, the first system will boot normally into normal mode,
and the Num Lock light will continue to blink.
After system 1 completes the boot process, the Num Lock light
will stop blinking, and the system will beep five times: This
signals
that
the
middleware
has
successfully
loaded
and
initialized all services, rules, and processes.
Note:
If the beeps are not heard, and the LED light continues to blink,
the middleware was unable to initialize all services, rules, and
processes.
If
this
happens,
please
contact
department of your security solution supplier.
100
the
service
Using the Security System
Configuring System 2 (Hot Standby Mode):
1.
Start system 2 as normal.
2.
Complete steps 3 through 6 as above, and click Save.
The system 2 will now shut down and reboot immediately. If you
have connected a keyboard to this machine, the Num Lock light
will flash.
When the system is in Hot Standby Mode, it will beep twice and
the LED display will stop blinking. System 2 recognizes system 1
through the data connection, and remains in Hot Standby Mode.
The High Availability system is now active.
System 2 will be updated at regular intervals over the data transfer
connection. Should the active system encounter an error, the standby
system will immediately and automatically change to normal mode
and take over the system’s functions.
101
Using the Security System
5.1.11. Shut down/Restart
Restart will shut the system down completely and reboot. Depending
on your hardware and configuration, a complete Restart can take up
to 5 minutes.
Restart:
1.
Under the System tab, open the Shut down/Restart menu.
2.
In the action drop-down menu, choose Restart.
3.
Begin the reboot by clicking Start.
4.
When asked Do you really want to restart?, click OK.
The action Shut down allows you to shut the system down, and
allows you to cleanly stop all running services.
For systems without a monitor or LCD display, the end of the shut
down process is signaled by an unending series of beeps at onesecond intervals.
Depending on your hardware and configuration, this process can take
up to 5 minutes. Only after the system has completely shut down,
signaled by the Power down message, should you turn off the
power. If the system is turned off without being shut down properly,
the system must check the consistency of the file system: this means
that the next boot will take longer. In the worst case, data may be
lost.
The system will beep five times in a row to signal a successful startup.
Shut down:
1.
Under the System tab, open the Shut down/Restart menu.
2.
In the Action drop-down menu, choose the Shut down action.
3.
Begin the shutdown by clicking Start.
4.
When asked Do you really want to shut down?, click OK.
102
Using the Security System
5.2. Networks and Services (Definitions)
The Definitions tab allows you to define networks and services for all
of the other configuration menus (e.g., the packet filter, VPN, proxies,
etc.) in one central location. This allows you to work with the names
you define, rather than struggling with addresses, ports, and network
masks. Another advantage is, that can group individual networks and
services together and configure them all at once. If, at a later date,
you assign certain settings to these groups, they will apply to all
networks and services contained therein. It is even possible to make
groups of groups. Local users for the proxy services can also be
defined here.
5.2.1.
Networks
In the Networks menu, the
hosts and networks and also
the
network
groups
are
defined.
The network table contains
static networks which have
been pre-defined. By default, the table contains next to the definitions
for the internal network card eth0 additional statically entered
networks. These statical networks cannot be edited or removed. The
hosts and networks can be grouped together. These groups will be
treated as individual hosts and networks and can belong to an
upstream group. The network types are represented by symbols.
The following pages contain a description of the different network
types available and of how they are defined.
103
Using the Security System
The network types are represented by symbols:
The Symbols
Icon
Spalte
Anzeige/Einstellung
Network type
Interface
Network type
Host/Server
Network type
Network
Network type
Network group
Network type
DNS server
Network type
IPSec user group
Adding Host:
1.
Under the Definitions tab, open the Networks menu.
2.
Click on the New Definition button.
3.
The entry window will open.
4.
Make the following settings:
Name: In the entry field, enter a unique host name.
This name will be used later, for example to configure packet
filter rules. Allowed characters are: The only allowed characters
are alphanumeric characters, minus (-), space ( ), and
underscore (_). Names may be up to 39 characters long.
Type: Select Host from the drop-down menu.
Address: Enter the IP-address in the entry field.
Comment: You can enter a host description in this entry field.
5.
Save the host by clicking on the Add Definition button.
If the definition is successful, the new Host will be entered in the
network table. You will now find this host under its name also in
104
Using the Security System
different other menus. You could, for example define this host under
System/Remote Syslog as Remote Syslog Server.
Adding Network:
1.
Under the Definitions tab, open the Networks menu.
2.
Click on the New Definition button.
The entry window will open.
3.
Make the following settings:
Name: In the entry field, enter a network name.
This name will be used later, for example to configure packet
filter rules. Allowed characters are: The only allowed characters
are alphanumeric characters, minus (-), space ( ), and
underscore (_). Names may be up to 39 characters long.
Type: Select Network from the drop-down menu.
Address/Netmask: Enter the IP address in the entry field and
select the network mask from the drop-down menu.
Comment: You can enter a network description in this entry
field.
4.
Save the network by clicking on the Add Definition button.
WebAdmin will check that your entries are valid.
After successful definition, the new network will appear in the
network table. The network name will also be available for use in
various configuration menus.
Using the network name you can, for instance, enable HTTP proxy
access for the new network under Proxies/HTTP.
105
Using the Security System
Adding DNS Server:
1.
Under the Definitions tab, open the Networks menu.
2.
Click on the New Definition button.
The entry window will open.
3.
Make the following settings:
Name: In the entry field, enter a unique DNS Server name.
This name will be used later, for example to configure packet
filter rules. Allowed characters are: The only allowed characters
are alphanumeric characters, minus (-), space ( ), and
underscore (_). Names may be up to 39 characters long.
Type: Select DNS Hostname from the drop-down menu.
Hostname: Enter the hostname in this entry field.
Comment: You can enter a DNS Server description in this entry
field.
4.
Save the host by clicking on the Add Definition button.
If the definition is successful, the new Host will be entered in the
network table. You will now find this host under its name also in
different other menus.
Defining Network Group:
1.
Under the Definitions tab, open the Networks menu.
2.
Click on the New Definition button.
The entry window will open.
3.
Make the following settings:
Name: In the entry field, enter a unique network group name.
This name will be used later, for example to configure packet
filter rules. Allowed characters are: The only allowed characters
106
Using the Security System
are alphanumeric characters, minus (-), space ( ), and
underscore (_). Names may be up to 39 characters long.
Type: Select Network Group from the drop-down menu.
Initial Members: From the selection field, select the network
card by pressing the Ctrl-key on the keyboard and selecting the
name with the mouse.
Comment: You can enter a network group description in this
entry field.
4.
Save the network group by clicking on the Add Definition
button.
After successful definition, the new network group will appear in the
network table. The network group name will also be available for use
in various configuration menus.
Defining IPSec user group: .
This definition contains only the Distinguished Name (DN). It is
used for incoming IPSec-connections, using X.509 certificates. If the
DN of the group corresponds to the one of the user, his virtual IPaddress will dynamically be added to the group.
1.
Under the Definitions tab, open the Networks menu.
2.
Click on the New Definition button.
The entry window will open.
3.
Make the following settings:
Name: In the entry field, enter a unique name for the IPsec user
group.
This name will be used later, for example to configure packet
filter rules. Allowed characters are: The only allowed characters
are alphanumeric characters, minus (-), space ( ), and underscore (_). Names may be up to 39 characters long.
Type: Select IPsec User Group from the drop-down menu.
107
Using the Security System
DN Template: For the VPN-ID-Type Distinguished Name you
will need the following data from the X.509 tab tree: Country
(C), State (ST), Local (L), Organization (O), Unit (OU) Common
Name (CN) and E-Mail Address (E).
The data must be listed in the same order as a certificate in this
entry field.
Comment: You can enter a IPsec user group description in this
entry field.
4.
Save the IPsec user group by clicking on the Add Definition
button.
After successful definition, the new IPSec user group will appear in
the network table. The IPSec user group name will also be available
for use in various configuration menus.
Filters
The Filters function allows
you
to
filter
networks
or
hosts with specific attributes
from the table. This function
considerably
enhances
the
management of huge networks, as networks of a certain type can be presented in a concise
way.
Filtering networks:
1.
Click on the Filters button.
The entry window will open.
2.
Enter the filter attributes in the fields listed. You don’t have to
define all attributes.
108
Using the Security System
Name: If you want to filter the networks by names, enter the
expression in the entry menu.
Type: Use this drop-down menu to filter the networks of a
specific type.
Address Values: If you wish to filter networks by specific
addresses, enter the IP-address in this entry field.
3.
To start the filter, click on the Apply Filters button.
Only the filtered networks will be displayed in the table. Next time
when you open the menu, the complete network table will be
displayed.
Further Functions
Editing Definitions : Click on the settings in the Name, Value and
Comment columns in order to open an editing window. You can then
edit the entries.
Deleting Definitions: Clicking on the symbol of the trash will delete
the definition from the table.
109
Using the Security System
5.2.2.
Services
The Services menu is used
to define the Services and
Service Groups.
Services
define
certain
types of traffic over networks like the Internet. A
service
is
defined
name,
a
protocol,
by
a
and
ports.
The following protocols can
be used: TCP, UDP, TCP/UDP, ICMP, ESP, AH and IP.
UDP uses port numbers between 0 and 65535 (inclusive) and is a
stateless protocol that uses no so-called ACK-Bit. Because it does not
keep state, UDP can be faster than TCP, especially when sending
small amounts of data. This statelessness, however, also means that
UDP cannot recognize when packets are lost or dropped. The
receiving computer does not signal the sender when it receives
packets successfully.
TCP connections also use port numbers from 0 to 65535 (inclusive).
Lost packets can be recognized through TCP and be requested again.
in a TCP connection, the receiver notifies the sender when a packet is
successfully received (connection related protocol). TCP sessions
begin with a three way handshake and are torn-down at the close
of the session.
The ESP and AH protocols are used for Virtual Private Networking
(VPN). These protocols are covered in chapter 0 on page 254.
The network table contains the defined services and groups. By
Default, the table contains the already pre-defined statically entered
services.
110
Using the Security System
Services can be grouped into Service Groups. These service groups
can be used the same way single services can, and can themselves be
included in other service groups. In the service table service groups
are labeled by the group symbole (--).
The definition of Service Groups is described on page 112.
Add Service:
1.
Under the Definitions tab, open the Service menu.
2.
Click on the New Definition button.
The entry window will open.
3.
Make the following settings:
Name: In the entry field, enter a unique Service name.
This name will be used later, for example to configure packet
filter rules. Allowed characters are: The only allowed characters
are alphanumeric characters, minus (-), space ( ), and
underscore (_). Names may be up to 39 characters long.
Type: Select Service from the drop-down menu.
Protocol: Select the Protocol from the drop-down menu.
Source/Destination Ports: In the left entry menu, enter the
Source Port, that is the Client Side of the service. In the right
entry menu, enter the Destination Port, that is the Server Side of
the service.
4.
The other settings depend on the selected protocol:
For the TCP and UDP protocols you need the following two
values. Entry options: A single port (e.g. 80) or a port range
(e.g. 1024:64000).
Source/Destination Ports: In the left-hand entry menu, enter
the Source Port, i.e. the Client Side of the service. In the right
hand entry menu, enter the Destination Port, i.e. the Server Side
of the service.
111
Using the Security System
The ESP and AH protocols are used for IPsec VPN connections.
The port entered here should be agreed upon with the remote
end of the IPSec VPN tunnel.
SPI: Enter a value from 256 to 65535. Values up to and including
255
are
reserved
by
the
Internet
Assigned
Numbers
Authority (IANA).
For the ICMP protocol, select a type of ICMP packet from the
ICMP type drop-down menu.
For the IP protocol enter the protocol number into the Protocol
Number entry field.
Comment: You can enter a service description in this entry field.
5.
Save the Services by clicking on the Add Definition button.
After successful definition, the new service will appear in the service
table.
Defining Service Group:
1.
Under the Definitions tab, open the Service menu.
2.
Click on the New Definition button.
The entry window will open.
3.
Make the following settings:
Name: In the entry field, enter a unique Service Group name.
This name will be used later, for example to configure packet
filter rules. Allowed characters are: The only allowed characters
are alphanumeric characters, minus (-), space ( ), and
underscore (_). Names may be up to 39 characters long.
Type: Select Service Group from the drop-down menu.
Initial Members: From the selection field, select the services by
pressing the Ctrl-key on the keyboard and selecting the name
with the mouse.
112
Using the Security System
4.
Save the Service Group by clicking on the Add Definition
button.
After successful definition, the new service group will appear in the
service table.
Filters
The Filters function allows you to filter Services with specific
attributes from the table. This function considerably enhances the
management of networks with many services, as services of a certain
type can be presented in a concise way.
Filtering services:
1.
Click on the Filters button.
The entry window will open.
2.
Enter the filter attributes in the fields listed. You don’t have to
define all attributes.
Name: If you want to filter the services by names, enter the
expression in the entry menu.
Protocol: This drop-down menu allows you to filter the services
by specific protocols.
Source Port: If you want to filter services by a specific source
port, enter it in this entry field.
Destination Port: If you want to filter services by a specific
target port, enter it in this entry field.
Comment: If you want to filter services by specific comments,
enter the expressions in this entry field.
3.
To start the filter, click on the Apply Filters button.
113
Using the Security System
Only the filtered services will be displayed in the table. Next time
when you open the menu, the complete service table will be
displayed.
Further Functions
Editing Definitions: Click on the settings in the Name, Value and
Comment columns in order to open an editing window. You can then
edit the entries.
Deleting Definitions: Clicking on the symbol of the trash will delete
the definition from the table.
5.2.3.
Users
In the Users menu Local
Users are added, if the use
of proxy services should be
limited to sepcial persons.
This is an alternative to
using an external user database. This menu allows you to define
which user has access to which proxy services. Available options are
HTTP-Proxy, SMTP-Proxy, SOCKS-Proxy, WebAdmin, L2TP over
IPSec and PPTP (Remote Access).
Security Note:
Normally, only the admin user has access to WebAdmin. The
password to WebAdmin should be changed at regular intervals.
114
Using the Security System
Add Local Users:
1.
Under the Definitions tab, open the Users menu.
2.
Click on the New Definition button.
The entry window will open.
3.
Make the following settings:
Username: In the entry field, enter a unique username for the
local user.
This username will be used later, for example to configure
packet filter rules. Allowed characters are: The only allowed
characters are alphanumeric characters, minus (-), space ( ),
and underscore (_). Names may be up to 39 characters long.
Password: Enter a password here.
Security Note:
Use a secure password! Your name spelled backwards is,
for example, not a secure password – while something like
xfT35$4 would be.
Comment: You can enter a local user description in this entry
field.
4.
Save the Local User by clicking on the Add Definition button.
The new User will then be displayed in the table.
5.
In the table, enable the services for the Local User.
Ar the beginning, no services are enabled for the user. Enable
the services, by clicking on the corresponding term.
Example:
HTTP = the HTTP Proxy is not enabled
HTTP = the HTTP Proxy is enabled
The available services are: HTTP Proxy, SMTP Proxy, SOCKS
Proxy, WebAdmin, L2TP over IPSec and PPTP (Remote
Access).
115
Using the Security System
PPTP Address: In PPTP connections also a static IP address can
be assigned to a remote host instead of a dynamic address from
a PPTP IP pool. In order to define a static IP, click on the field in
the PPTP Address column and enter the address in the entry
field.
Click the Save button to save your changes. In order to interrupt
this process, click on the Cancel button.
For more information on PPTP VPN Access, please refer to
chapter 5.3.6 on page 169.
Filters
The Filters function allows
you to filter Users with specific attributes from the table.
This function considerably enhances the management of huge network configurations, as users of
a certain type can be presented in a concise way.
Filtering users:
1.
Click on the Filters button.
The entry window will open.
2.
Enter the filter attributes in the fields listed. You don’t have to
define all attributes.
Username: If you want to filter the users by username, enter
the expression in the entry field.
Comment: If you want to filter users by specific comments,
enter the expressions in this entry field.
3.
116
To start the filter, click on the Apply Filters button.
Using the Security System
Only the filtered users will be displayed in the table. Next time when
you open the menu, the complete user table will be displayed.
Further Functions
Editing Local Users: Click on the settings in the Name, Password,
PPTP Address and Comment columns in order to open an editing
window. You can then edit the entries.
Deleting Local Users: Clicking on the symbol of the trash can will
delete the definition from the table.
117
Using the Security System
5.3. Network Settings (Network)
The Network tab contains menus which allow you to configure network cards and virtual interfaces, as well as to perform networkspecific configuration and management tasks.
5.3.1.
Hostname/DynDNS
Firewall Hostname
Hostname: Enter the hostname for the security system in this entry field. Example: FIREWALL.mydomain.com
A Hostname or domain name may contain alphanumeric, period and
minus characters. At the end there must be an alphabetic designator,
such as
„com“, „de“ or „org“. The Hostname will appear in the
subject line of all Notification E-Mails.
Save your entries by clicking the Save button.
Note:
The Hostname will appear in the subject line of all Notification EMails to the Administrator.
Dynamic DNS
Dynamic DNS addresses
a device or a VPN receiver
through a DNS decryptable
name.
applicable
The
IP
respective
address
is
stored for each name to a public DNS server in the Internet at each
connection. The device can always be reached through this name - as
118
Using the Security System
long as it online, at least. A mobile user, for example can access his
company network through Dynamic DNS, even if the company only
uses standard DSL connections with dynamic IP addresses. In
addition to VPN applications, Dynamic DNS can also be used for
remote maintenance and control.
Defining Dynamic DNS Servers:
1.
In the Network tab, open the Hostname/DynDNS menu.
2.
Enable the function by clickin on the Enable button in the
Status column.
The entry window will open.
3.
Make the following settings:
Hostname: In the entry field, enter the hostname.
Username: In the entry field, enter the username.
Password: In the entry field, enter the password.
4.
Save your settings by clicking on the Save button.
5.3.2.
Interfaces
A firewall requires at least
two
network
cards
in
order to securely connect an
internal network (LAN) to an
external one (the Internet).
In our examples, the Network card eth0 is always
the interface connected to
the internal network. Network
card
eth1
is
the
interface connected to the
external network (e.g., to
119
Using the Security System
the Internet). These interfaces are also called the trusted and
untrusted interfaces, respectively.
Network cards are automatically recognized during the installation: if
new network cards are added later, a new installation will be
necessary. In order to re-install the system, simply make a backup of
your configuration, install a new copy of the software, and re-load
your backed-up configuration.
As is shown in the graphic at left, the firewall
must be the only point of contact between
internal networks and external ones. All data
must pass through the security system.
We
strongly
mend
necting
recom-
against
both
coninternal
and external interfaces
to one hub or switch –
except if the switch is
configured as a VLAN switch. There might be
wrong ARP resolutions (Address Resolution
Protocol)
(ARP
clash),
which
cannot
be
administered by all operating systemen (such
as those from Microsoft). Therefore, one physical network segment
has to be used for each firewall network interface.
The Interfaces menu allows you to configure and manage all
network cards installed on the security system and also all interfaces
with the external network (Internet) and interfaces to the internal
networks (LAN, DMZ).
120
Using the Security System
Note:
While planning your network topology and configuring the security
system, take care to note which interface is connected to which
network. In most configurations, the network interface with SysID
eth1 is chosen as the connection to the external network.
In order to install the High Availability (HA) system, the selected
network cards on both systems must have the same SysID. Installing
the HA system is described in more detail in chapter 5.1.10 on page
97.
The following sections explain how to use the Current Interface
Status and Hardware List windows to manage the various Interface types.
Current Interface Status
This window allows you
to configure both, logical
and virtual interfaces.
The
table
interfaces
lists
which
all
have
already been configured.
The graphic at left shows the Interfaces menu after three Ethernet
network cards have been configured.
During the installation, you will have configured the eth0 interface.
This interface is the connection between the security solution and the
internal network (LAN). By default, this network card is named
Internal. The table displays all of the most important information
about the interfaces: the administrative status (enabled/disabled,
indicated by a green or red status light), current connection status
(Up/Down), Name (Name), ID (Sys ID), network card type
(eth/wlan) as well as IP address and network mask (Parameters).
Click the status light in the Admin column to administratively enable
121
Using the Security System
or disable the interface. The functions in the Actions column allow
you to edit the configuration of the interface, or to delete it entirely.
With this Internet security system, you assign one Name and also a
specific network card to one virtual interface. Three logical networks
will then be defined for each configured interface:
•
An interface (NAME (Address)), consisting of the defined IP
address and the network mask 255.255.255.255 (Host)
•
An interface (NAME (Network)), consisting of the defined IP
address and the network mask 255.255.255.255 (Network)
•
A Broadcast (NAME (Broadcast)) network, consisting of the
broadcast
IP
for
this
interface
and
the
network
mask
255.255.255.255 (Host)
The networks are shown in the Networks menu. If an interface is
configured using a dynamic addressing scheme, for example through
DHCP or PPPoE, these settings are automatically updated. This
means that all functions (for example, packet filter rules) configured
with these aliases will automatically use the correct addresses.
Hardware List
This table lists all network cards installed on
the security system, together with the relevant hardware information. The table shows, for
example, the system-assigned ID (Sys ID), type of network card,
hardware (MAC) address (Name/Parameters), and PCI bus information: Bus/Device/Function (PCI Device ID).
122
Using the Security System
Error:
The Hardware List table doesn’t list all of the network cards.
Possible Causes:
The missing network cards were added after the installation of
the security system, or were not recognized during installation. Please contact the support department of your security
system provider.
Attention:
If you change the IP Address of the internal network card (eth0),
you may lock yourself out.
123
Using the Security System
5.3.2.1.
Standard Ethernet Interface
To configure a network card
for a standard Ethernet connection to an internal or external
network,
you
must
configure the card with an IP
address and netmask.
All network cards installed
on the security system are
shown
in
the
Hardware
List.
Configuring a Standard Ethernet Connection:
1.
In the Network tab, open the Interfaces menu.
2.
Click on the New button.
The Add Interface window will open.
3.
In the Name entry field, enter a descriptive name for the
interface. (example: Externally for an Internet connection)
4.
Use the Hardware drop-down menu to select a network card.
Tip:
For an external connection (e.g., to the Internet) choose the
card with Sys ID eth1.
5.
Use the drop-down menu Type to select Standard Ethernet
Interface.
Please note that one network card cannot be used as both a
Standard ethernet interface and a PPP over Ethernet
(PPPoE-DSL) or PPPTP over Ethernet (PPPoA-DSL) connection simultaneously.
124
Using the Security System
6.
Now make the specific settings for this interface type:
Address: If you wish to use a static IP address for this interface,
select Static from the drop-down menu and enter the address to
use in the entry field. If you wish to have a gateway dynamically
assigned via DHCP, select Assign by DHCP from the drop-down
menu.
Netmask: If you wish to use a statically defined network mask
for this interface, use the drop-down menu to select Static and
enter the netmask to use in the entry field. If you wish to have a
netmask dynamically assigned via DHCP, select Assign by
DHCP from the drop-down menu.
Default Gateway: If you wish to use a statically defined default
gateway, use the drop-down menu to select Static and enter the
address of the gateway in the entry field. If you wish to have a
gateway dynamically assigned via DHCP, select Assign by
DHCP from the drop-down menu. Otherwise, select None.
Proxy ARP: When this function is enabled, the security system
will answer ARP requests on the selected interface for all known
networks. This system will thus act as a proxy on this interface
for all of the other directly-connected networks.
This function is only required in special cases, for example when
an attached network cannot be configured with normal routing
entries (e.g., when the network includes a router over which you
have no control).
By default, the Proxy ARP function is disabled (Off). To enable
it, select On from the drop-down menu.
Uplink Failover on Interface: This function will only displayed,
if the parameter Assign by DHCP or Static has been selected in
the Default Gateway drop-down menu.
If a network card is an interface to the Internet (e.g. 2 Megabit
fixed connection) you can configure a standby connection by a
second Internet access (e.g. DSL-connection) and an additional
125
Using the Security System
network card. If the primary connection fails, the uplink will
automatically be set up through the second Internet access.
Note:
You need two separate Internet accesses and an additional
network card for the Uplink Failover on Interface connection.
Uplink Failover on Interface is by default disabled (Off). If
you wish to use this network card as primary Internet connection, then configure it in the Primary Interface drop-down
menu. If this network card shall contain the standby connection,
select the setting Backup Interface.
Uplink Failover check IP: Once the Uplink Failover on
Interface function has been enabled, this entry field will be
displayed. Enter the IP-address of a host that replies to ICMPping-requests (e.g., the DNS server of your ISP). The security
system will send ping requests to this host: if no answer is
received, the backup-interface will be enabled by the failover. In
this entry field, there must always be an IP-address for the
failover.
QoS Status: In order to use Quality of Service (QoS) bandwidth management on an interface, enable this option. To enable
the Quality of Service (QoS) function, select On from the
drop-down menu.
Important note:
For the bandwidth management Quality of Service (QoS) you
must define the values for Uplink Bandwidth (kbits) and
Downlink Bandwidth (kbits). These values are used as basis
for the bandwidth management system: incorrect values can
lead to poor management of the data flow. The Quality of
Service (QoS) function is described in chapter 5.5.1.
Uplink Bandwidth (kbits): These settings will only appear, if
the QoS function is enabled. In this entry menu, enter the
126
Using the Security System
available bandwidth for the Uplink in full kilobits. This value can
be determined either from the values of the upstream interface
or from the router. On an interface to the Internet, this value
corresponds to the bandwidth of the Internet connection - on an
ADSL access the Uplink bandwidth amounts to 128 kBit/s and on
a 2-Megabit fixed connection to 2048 kBit/s.
Downlink Bandwidth (kbits): These settings will only appear,
if the QoS function is enabled. In this entry menu, enter the
available bandwidth for the Downlink in full kilobits. On an
interface
to
the
Internet,
this
value
corresponds
to
the
bandwidth of the Internet connection - on an ADSL access the
Uplink bandwidth amounts to 768 kBit/s and on a 2-Megabit
fixed connection to 2048 kBit/s.
MTU Size: The MTU is the size (in bytes) of the largest
transmittable packet. MTU stands for Maximum Transfer Unit.
For connections, using the TCP/IP protocol, the data will be
grouped into packets. A maximum size will be defined for these
packets. Packets larger than this value will be considered too
long for the connection and fragmented into smaller ones before
transmission. These data packets will be sent again. However,
the performance can be limited, if the upper value is too low.
The largest possible MTU for an Ethernet interface is 1500 Bytes.
The following values are the defaults for the Standard Ethernet
Interface: 1500 Byte.
7.
Confirm these settings by clicking Add.
The system will now check the address and netmask for
semantic validity. After a successful check, the new interface
will appear in the Current Interface Status table. The interface
is not yet enabled (status light is red)
8.
Enable the interface by clicking the status light.
The interface is now enabled (status light shows green). The Oper
column will at first show that the interface is Down: the system
127
Using the Security System
requires a short time to configure and load the settings. When the
message Up appears, the interface is fully operational.
5.3.2.2.
Additional Address on Ethernet
Interface
One network card can be
configured with multiple additional
IP
addresses
(also
called IP aliases). This function allows you to manage
multiple logical networks on
one physical network card. It can also be used to assign further
addresses to a security system running NAT. NAT is described in
further detail in chapter 5.3.4 on page 157. Each network card can be
configured with up to 255 additional addresses.
Adding additional addresses to a network card:
1.
In the Network tab, open the Interfaces menu.
2.
Click on the New button.
The Add Interface window will open.
3.
In the Name entry field, enter a descriptive name for the
interface.
4.
Use the Hardware drop-down menu to select a network card.
5.
Use the Type drop-down menu to select Additional address on
Ethernet interface.
6.
Now make the specific settings for this interface type:
Address: For this interface type, the address must be statically
defined. This kind of interface can only use static addresses.
128
Using the Security System
Netmask: This interface type requires a statically defined
netmask. This kind of interface can only use static masks.
Default Gateway: If you wish to use a default gateway with
this interface, select Static from the drop-down menu and enter
the gateway address in the entry field. Otherwise, select None.
7.
Confirm these settings by clicking Add.
The system will now check the address and netmask for
semantic validity. After a successful check, the new interface
will appear in the Current Interface Status table. The interface
is not yet enabled (status light is red)
8.
Enable the interface by clicking the status light.
The interface is now enabled (status light shows green). The Oper
column will at first show that the interface is Down: the system
requires a short time to configure and load the settings. When the
message Up appears, the interface is fully operational.
129
Using the Security System
5.3.2.3.
Wireless LAN
The industry standards IEEE 802.11 apply to Wireless LAN. This
Internet security system supports the IEEE 802.11b protocol. This
standard uses radio signals in the ISM frequencies (in the 2.4 GHz
band) to communicate between nodes. ISM stands for Industrial
Scientific and Medical. The ISM frequencies have been specifically
allocated for unlicensed communication by industrial, scientific, and
medical organizations, and are thus available for cost-free private
use. The IEEE 802.11b standard allows for a maximum bandwidth of
11 Mbit/s. When planning your network design, however, please note
that bandwidth actually available will be smaller when the distances
between nodes are large.
Important note:
In order to configure a Wireless LAN, you will need a PCMCIA card
with a Prism2, Prism2,5- or Prism3-compatible chipset. The hardware supported by the security system is listed in the Hardware
Compatibility List for Astaro Security Linux available
at
http://docs.astaro.org.
The wireless LAN interface on the security system can be configured
either as a Wireless LAN Access Point or a Wireless LAN Station.
The Wireless LAN Access Point mode connects wireless nodes with
one another: its function is analogous to that of a hub in a traditional
wired network. Wireless nodes can also communicate with the (wired)
LAN through the security system.
In the Wireless LAN Station mode, the security system functions as
a normal node on an existing wireless network. Only in this mode can
the system acquire an IP address through DHCP.
Wireless LAN Security
The 802.11 standard includes the WEP standard for encrypting radio
communications. WEP stands for Wired Equivalent Privacy. This
encryption method is based on the RC4 cipher, and uses a secret
130
Using the Security System
string to encrypt and decrypt messages. Activating WEP requires this
secret key to be configured on all interfaces on the wireless network.
All transmissions over the network are encrypted with this key at the
sending station. and then decrypted at the receiving station. Without
this key, the data cannot be decrypted.
This security system can also use WEP for Authentication. A
computer attempting to connect to the network which is not
configured with the correct key will be dropped at the access point.
The Wireless LAN Access Point mode also allows stations to be
selectively granted access to the network on the basis of MAC
Address. Normally, in the interest of flexibility, a wireless LAN will
allow any new node onto the network as long as it is configured with
the correct WEP settings. An administrator may choose, however, to
control which nodes should have access: Such a filter can be
configured to allow only certain nodes – for instance, the one
identified by MAC address 00:04:76:26:65:4C – onto the network.
When a new node attempts to join the network, the security system
will check its MAC address: if the hardware address is in the list of
allowed nodes, it will be permitted to join, otherwise the connection
will be dropped.
This security solution supports two kinds of MAC address filter:
negative and positive. A negative filter allows all hardware addresses except those on the list to join the network. In the access
control you only define those network cards that should not be
accessed by Wireless LAN.
A positive filter, on the other hand, first of all excludes all MAC
addresses. In the access control you define explicitly those network
cards that should can be accessed by Wireless LAN.
If at all possible, a positive filter should be used, which is by far safer.
The following settings are required to configure a wireless LAN
PCMCIA card:
131
Using the Security System
•
SSID: An acronym for Service Set Identifier: this is essentially
the name of the network. More than one wireless LAN can coexist
in the same physical space provided that they have different
names or use separate channels. The name of a network can be
chosen freely: the only requirement is that it not contain any
space characters.
If you are configuring a Wireless LAN Station interface to
connect to an already-existing wireless network, this must be the
name of that network. The name can be up to 32 characters long.
•
Channel: This system must be manually configured with the radio
channel to use. If other wireless networks are in the area, you
should chose an unused channel for your network.
Please also note that only certain channels may be used in certain
countries:
•
Country
Channel
Country
Channel
USA & Canada
1 to 11
Spain
10/11
Europe (ETSI)
1 to 14
France
10 to 13
Japan
1 to 14
WEP: In order to use WEP encryption, you will need at least one
WEP key - up to four can be used. You can choose between a 40
bit and 104 bit keys. A 40-bit key requires 5 hexadecimal
numbers, while a 104-bit key requires 13 numbers. Please note
that a hexadecimal number is two characters, each either a
number (0-9) or a letter (A-F).
Example of a 40-bit key: 17:A5:6B:45:23
•
Access Mode (only for Wireless LAN Access Point mode): If you
wish to use the MAC address filter, you must compile a list of the
MAC addresses which are explicitly allowed to connect to the
network (positive filter), or which are explicitly not allowed to
(negative filter).
132
Using the Security System
How to determine the MAC address of a computer is described in
the next section.
Determining the MAC address:
If you have not yet installed your network card, you can simply
examine it to determine its MAC address: the unique MAC address is
usually printed on the card itself.
If the wireless LAN is already being used and you wish to install a new
MAC filter, you can use the following commands on the mobile nodes
to determine the MAC address. If you are configuring a small wireless
LAN, the mobile computers are MS Windows computers, and you have
physical access to them, follow these steps:
1.
Open the Command Prompt.
2.
The Command Prompt can be found in the Start menu, under
Programs/Accessories/Command Prompt.
3.
Enter the following command at the prompt:
ipconfig –all
4.
Press the Enter key.
The Physical Address row contains the MAC address, for
example 00-04-76-26-65-4C.
5.
Close the command prompt.
If you have a larger network, you can use the ping program under MS
Windows to determine the MAC addresses of remote nodes:
1.
Make sure that the remote computer whose MAC address you
wish to check is turned on and connected to the network.
2.
Open the Command Prompt.
The Command Prompt can be found in the Start menu, under
Programs/Accessories/Command Prompt.
133
Using the Security System
3.
Ping the destination computer by using the following command:
ping IP Address (e.g. ping 192.168.2.15)
4.
Press the Enter key.
If the destination computer is reachable, you will receive the
ping replies and some information about network latency.
5.
Enter the following command:
arp –g
6.
Press the Enter key.
Your computer’s local ARP table will now be displayed. The
Physical Address column of this table shows the MAC address
for each known IP address.
In order to connect to a remote computer on the same subnet, the
local computer addresses Ethernet frames to the remote computer’s
MAC address. In order to do this, it must first determine the remote
hardware address by issuing an ARP request. When you issue the ping
request, your local computer automatically determines the remote
computer’s MAC address and stores it in the local ARP table for future
use.
If you wish to configure a PCMCIA Card for the Wireless LAN as an
Access Point, complete the following steps. Configuration as a
Station is described on page 137.
Configuring a Wireless LAN Access Point:
1.
In the Network tab, open the Interfaces menu.
2.
Click on the New button.
The Add Interface window will open.
3.
In the Name entry field, enter a descriptive name for the
interface.
134
Using the Security System
4.
Use the Hardware drop-down menu to select the Wireless LAN
network card.
5.
Use the Type drop-down menu to select the Wireless LAN
Access Point interface type.
6.
Fill in the required settings for the Wireless LAN Access Point.
Address: Assign an IP address for the access point. For this
interface type, the address must be statically defined. Enter the
address into this entry field.
Netmask: This interface type requires a statically defined
netmask. Enter the network mask into this entry field.
Default Gateway: If you wish to use a default gateway with
this interface, select Static from the drop-down menu and enter
the gateway address in the entry field. Otherwise, select None.
SSID: Enter the network name for the wireless network here.
Enter a string without space characters here. This should be a
string up to 32 characters long.
Channel: Use the drop-down menu to select a frequency
channel for the network.
Use WEP: If you wish to use WEP encryption on the wireless
LAN, select Yes from the drop-down menu.
Security Note:
You should always use WEP encryption, as an unencrypted
network presents a serious threat to network security.
If you select No from the drop-down menu, the WEP-specific
configuration options will be ignored by the system.
WEP Authentication: If you wish to enable WEP authentication,
select Yes from the drop-down menu. All nodes on the wireless
network must be configured with the correct WEP Key.
Require WEP: If you do not wish to allow nodes not supporting
WEP onto the wireless network, choose Yes here.
135
Using the Security System
WEP Key: Enter the WEP key to use in the WEP Key 0 through
3 entry fields. In order to use WEP encryption, you will need at
least one WEP key - up to four can be used.
For a 40-bit key, enter a string with 5 hexadecimal digits
separated by colons. In order to use a 104-bit key, enter a string
of 13 hexadecimal digits separated by colons. The string must
consist of hexadecimal digits. Please note that a hexadecimal
number is two characters, each either a number (0-9) or a letter
(A-F).
Example of a 40-bit key: 17:A5:6B:45:23
Default WEP Key: Use the drop-down menu to choose one of
the defined WEP Keys 0-3 which should be used as the default
key. This key will be used as the current key, which all the other
nodes must use to access the wireless network.
Access Mode: Choose the filter mode for the wireless LAN. If all
nodes should be allowed access (subject, of course, to WEP
restrictions), select All stations can get access.
If you wish to configure a positive filter select Stations in
Allowed MAC addrs can get access. To use a negative filter,
choose Stations in Denied MAC addrs can not get access.
Allowed MAC addrs: If you have chosen to use a positive
filter, enter the MAC addresses of nodes allowed to access the
wireless network in the access control list.
The access control list function is identical to the ordered list
and is described in chapter 4.3.4 on page 39.
Denied MAC addrs: If you have chosen to use a negative
filter, enter the MAC addresses of nodes explicitly not allowed to
access the network in the access control list.
The access control list function is identical to the ordered list
and is described in chapter 4.3.4 on page 39.
7.
136
Confirm these settings by clicking Add.
Using the Security System
The system will now check the address and netmask for
semantic validity. After a successful check, the new interface
will appear in the Current Interface Status table. The interface
is not yet enabled (status light is red)
8.
Enable the interface by clicking the status light.
The interface is now enabled (status light shows green). The Oper
column will at first show that the interface is Down: the system
requires a short time to configure and load the settings. When the
message Up appears, the interface is fully operational.
Configuring a Wireless LAN Station:
1.
In the Network tab, open the Interfaces menu.
2.
Click on the New button.
The Add Interface window will open.
3.
In the Name entry field, enter a descriptive name for the
interface.
4.
Use the Hardware drop-down menu to select the Wireless LAN
network card.
5.
Use the Type drop-down menu to select the Wireless LAN
Station interface type.
6.
Fill in the required settings for the Wireless LAN Station.
Address: Assign an IP address for the station. If you wish to use
a static IP address for this interface, select Static from the dropdown menu and enter the address to use in the entry field. If
you wish to have a gateway dynamically assigned via DHCP,
select Assign by DHCP from the drop-down menu.
Netmask: If you wish to use a statically defined network mask
for this interface, use the drop-down menu to select Static and
enter the netmask to use in the entry field. If you wish to have a
137
Using the Security System
netmask dynamically assigned via DHCP, select Assign by
DHCP from the drop-down menu.
Default Gateway: If you wish to use a statically defined default
gateway, use the drop-down menu to select Static and enter the
address of the gateway in the entry field. If you wish to have a
gateway dynamically assigned via DHCP, select Assign by
DHCP from the drop-down menu. Otherwise, select None.
SSID: Enter the network name for the wireless network here. If
you wish to establish a connection with an already existing
Wireless LAN, you must enter the existing network name.
Use WEP: If you wish to use WEP encryption on the wireless
LAN, select Yes from the drop-down menu.
Security Note:
You should always use WEP encryption, as an unencrypted
network presents a serious threat to network security.
If you select No from the drop-down menu, the WEP-specific
configuration options will be ignored by the system.
WEP Authentication: If you wish to enable WEP authentication,
select Yes from the drop-down menu. All nodes on the wireless
network must be configured with the correct WEP Key.
Require WEP: If you do not wish to allow nodes not supporting
WEP onto the wireless network, choose Yes here.
WEP Key: Enter the WEP key to use in the WEP Key 0 through
3 entry fields. In order to use WEP encryption, you will need at
least one WEP key - up to four can be used.
For a 40-bit key, enter a string with 5 hexadecimal digits
separated by colons. In order to use a 104-bit key, enter a string
of 13 hexadecimal digits separated by colons. The string must
consist of hexadecimal digits. Please note that a hexadecimal
number is two characters, each either a number (0-9) or a letter
138
Using the Security System
(A-F).
Example of a 40-bit key: 17:A5:6B:45:23
Default WEP Key: Use the drop-down menu to choose one of
the defined WEP Keys 0-3 which should be used as the default
key. This key will be used as the current key, which all the other
nodes must use to access the wireless network.
7.
Confirm these settings by clicking Add.
The system will now check the address and netmask for
semantic validity. After a successful check, the new interface
will appear in the Current Interface Status table. The interface
is not yet enabled (status light is red)
8.
Enable the interface by clicking the status light.
The interface is now enabled (status light shows green). The Oper
column will at first show that the interface is Down: the system
requires a short time to configure and load the settings. When the
message Up appears, the interface is fully operational.
139
Using the Security System
5.3.2.4.
Virtual LAN
Virtual LAN (VLAN) technology allows a network to
be segregated into multiple
smaller network segments at
the Ethernet level (layer 2).
This can be useful, for instance, when security considerations require that certain clients only be allowed
to communicate with certain
other ones. In large networks, this can also be useful to connect
physically separate clients on the same logical network segment.
A VLAN-capable switch can assign ports to distinct groups. For
example, a 20 port switch could assign ports 1 through 10 to VLAN 1,
and ports 11 through 20 to VLAN 2. With such a configuration, a
computer on port 1 would not be able to communicate with a
computer on port 11. The technology essentially allows one physical
switch to be divided into two logical ones.
In order to connect the security system to the virtual LANs, the
system requires a network card with a tag-capable driver. A tag is a
4-byte header attached to packets as part of the Ethernet header. The
tag contains the number of the VLAN that the packet should be sent
to: the VLAN number is a 12-bit number, allowing up to 4095 virtual
LANs. The WebAdmin tool refers to this number as the VLAN Tag.
The tagged packets are only used to communicate between the VLANcompatible switch and the security system, the other computers on
the network do not need to have tag-compatible network cards. The
port on the switch connected to the security system must also be
configured as an untagged port. Most VLAN-compatible switches can
be configured by using a terminal program over a serial interface.
140
Using the Security System
Example configuration:
The
graphic
at
left
shows an office where
computers are distributed
across
two
floors. Each floor has
a
separate
switch,
and the each computer is connected to
the switch on its floor.
In this configuration, PC1 and PC2 on the first floor and PC4 on the
second floor will be connected together on VLAN 10. PC3, PC5 and
PC6 will be connected together on VLAN 20.
The two switches must be configured as follows:
Switch a
Port
Switch b
VLAN Tag tagged/
Port
VLAN Tag tagged/
untagged
untagged
1
10, 20
T
1
10, 20
T
2 (PC1)
10
U
2 (PC4)
10
U
3 (PC2)
10
U
3 (PC5)
20
U
4 (PC3)
20
U
4 (PC6)
20
U
5
10,20
T
In this configuration, it seems to PC3 as though it were connected
through a single switch to PC5 and PC6.
In order to connect the computers to an external network (e.g., the
Internet), the interface on the security system (in the example, this is
eth2) must be configured to support the VLANs.
141
Using the Security System
Attention:
In order to configure a Virtual LAN interface, you will need a
network card with a tag-capable driver. The hardware supported by
the security system is listed in the Hardware Compatibility List for
Astaro Security Linux available at http://docs.astaro.org.
Configuring a Virtual LAN:
1.
In the Network tab, open the Interfaces menu.
2.
Click on the New button.
The Add Interface window will open.
3.
In the Name entry field, enter a descriptive name for the
interface.
4.
Use the Hardware drop-down menu to select a network card.
5.
Use the drop-down menu Type to select VLAN Ethernet
interface.
6.
Fill in the required settings for the VLAN Ethernet Interface
type of interface:
Address: Assign an IP address for the virtual interface. If you
wish to use a static IP address for this interface, select Static
from the drop-down menu and enter the address to use in the
entry field. If you wish to have a gateway dynamically assigned
via DHCP, select Assign by DHCP from the drop-down menu.
Netmask: If you wish to use a statically defined network mask
for this interface, use the drop-down menu to select Static and
enter the netmask to use in the entry field. If you wish to have a
netmask dynamically assigned via DHCP, select Assign by
DHCP from the drop-down menu.
Default Gateway: If you wish to use a statically defined default
gateway, use the drop-down menu to select Static and enter the
142
Using the Security System
address of the gateway in the entry field. If you wish to have a
gateway dynamically assigned via DHCP, select Assign by
DHCP from the drop-down menu. Otherwise, select None.
VLAN Tag: Enter the VLAN tag to use for this interface.
Uplink Failover on Interface this function will only be
displayed if the Assign by DHCP or Static is selected in the
Default Gateway drop-down menu.
You can configure a standby connection through a second
interface. If the primary connection fails, the uplink will
automatically be set-up through the second interface.
Uplink Failover on Interface is by default disabled (Off). If
you wish to use this virtual interface as primary connection,
select Primary Interface from the drop-down menu. If this
interface shall contain the standby connection, select the
Backup Interface configuration.
Uplink Failover check IP: Once the Uplink Failover on
Interface function has been enabled, this entry field will be
displayed. Enter the IP-address of a host that replies to ICMPping-requests. The security system will send ping requests to
this host: if no answer is received, the backup-interface will be
enabled by the failover. In this entry field, there must always be
an IP-address for the failover.
QoS Status: In order to use Quality of Service (QoS)
bandwidth management on an interface, enable this option. To
enable the Quality of Service (QoS) module, select On from
the drop-down menu.
143
Using the Security System
Important Note:
For the bandwidth management Quality of Service (QoS) you
must define the values for Uplink Bandwidth (kbits) and
Downlink Bandwidth (kbits). These values are used as basis
for the bandwidth management system: incorrect values can
lead to poor management of the data flow. The Quality of
Service (QoS) function is described in chapter 5.5.1.
Uplink Bandwidth (kbits): These settings will only appear, if
the QoS function is enabled. In this entry menu, enter the
available bandwidth for the Uplink in full kilobits. This value can
be determined either from the values of the upstream interface
or from the router.
Downlink Bandwidth (kbits): These settings will only appear,
if the QoS function is enabled. In this entry menu, enter the
available bandwidth for the Downlink in full kilobits.
MTU Size: The MTU is the size (in bytes) of the largest transmittable packet. MTU stands for Maximum Transfer Unit. For
connections, using the TCP/IP protocol, the data will be grouped
into packets. A maximum size will be defined for these packets.
Packets larger than this value will be considered too long for the
connection and fragmented into smaller ones before transmission. These data packets will be sent again. However, the performance can be limited, if the upper value is too low.
The largest possible MTU for an Ethernet interface is 1500 Bytes.
The following values are the defaults for the VLAN Ethernet
Interface: 1500 Byte.
7.
Confirm these settings by clicking Add.
The system will now check the address and netmask for
semantic validity. After a successful check, the new interface
will appear in the Current Interface Status table. The interface
is not yet enabled (status light is red).
144
Using the Security System
8.
Enable the interface by clicking the status light.
The interface is now enabled (status light shows green). The Oper
column will at first show that the interface is Down: the system
requires a short time to configure and load the settings. When the
message Up appears, the interface is fully operational.
The new virtual interface will appear in the Hardware Device
Overview just as an additional IP address (IP alias) on a standard
Ethernet network card would. The Sys ID of this virtual interface is
composed of the SysID of the network card and the number of the
VLAN tag.
5.3.2.5.
PPPoE-DSL Connection
This interface type is used
to connect to the Internet
over
a
DSL
connection
using the PPP over Ethernet protocol. The configuration will require the DSL
connection information, including username and password,
provided
by
your
Internet Service Provider.
Note:
The installation and specific settings required for DSL connections is
described in the DSL Network guidebook. Also note that, once the
DSL connection is activated, the security system will be connected to
your ISP 24 hours a day. You should therefore ensure that your ISP
bills on a flat-rate or bandwidth-based system rather than based on
connection time. The DSL Network guidebook is available at
http://docs.astaro.org.
145
Using the Security System
Configuring PPP over Ethernet (PPPoE-DSL):
1.
In the Network tab, open the Interfaces menu.
2.
Click on the New button.
The Add Interface window will open.
3.
In the Name entry field, enter a descriptive name for the
interface.
4.
Use the Hardware drop-down menu to select a network card.
Tip:
For an external connection (e.g., to the Internet) choose the
card with Sys ID eth1.
You cannot choose a network card that has already been
configured with a primary network address.
5.
Use the Type drop-down menu to select the PPP over Ethernet
(PPPoE-DSL) connection interface type.
You will need the connection settings provided by your ISP to
configure the following settings.
Address: If you have not been assigned a static IP address by
your provider, keep the default Assigned by remote setting
here. If you have a static IP address, choose Static from the
drop-down menu and enter the address in the entry field.
Default Gateway: You should probably keep the default setting
Assigned by remote. Other possible values are Static and
None.
Username: Enter the username, provided by your ISP.
Password: Enter the password, provided by your ISP.
Uplink Failover on Interface this function will only be
displayed if the Assign by DHCP or Static is selected in the
Default Gateway drop-down menu.
146
Using the Security System
You can configure a standby connection through a second
interface. If the primary connection fails, the uplink will
automatically be set-up through the second interface.
Note:
You need two separate Internet accesses and one additional
network card for the Uplink Failover on Interface function.
Please, note that the Security system only supports one DSLconnection. A standby connection for accessing the Internet can
therefore only consist, for example, of a fixed connection and a
DSL access.
Uplink Failover on Interface is by default disabled (Off). If
you wish to use this virtual interface as primary connection,
select Primary Interface from the drop-down menu. If this
interface shall contain the standby connection, select the
Backup Interface configuration.
Uplink Failover check IP: Once the Uplink Failover on
Interface function has been enabled, this entry field will be
displayed. Enter the IP-address of a host that replies to ICMPping-requests (e.g., the DNS server of your ISP). The security
system will send ping requests to this host: if no answer is
received, the backup-interface will be enabled by the failover. In
this entry field, there must always be an IP-address for the
failover.
QoS Status: In order to use Quality of Service (QoS)
bandwidth management on an interface, enable this option. To
enable the Quality of Service (QoS) module, select On from
the drop-down menu.
147
Using the Security System
Important note:
For the bandwidth management Quality of Service (QoS) you
must define the values for Uplink Bandwidth (kbits) and
Downlink Bandwidth (kbits). These values are used as basis
for the bandwidth management system: incorrect values can
lead to poor management of the data flow. The Quality of
Service (QoS) function is described in chapter 5.5.1.
Uplink Bandwidth (kbits): These settings will only appear, if
the QoS function is enabled. In this entry menu, enter the
available bandwidth for the Uplink in full kilobits. This value can
be determined either from the values of the upstream interface
or from the router. On an interface to the Internet, this value
corresponds to the bandwidth of the Internet connection - on an
ADSL access the Uplink bandwidth amounts to 128 kBit/s and on
a 2-Megabit fixed connection to 2048 kBit/s.
Downlink Bandwidth (kbits): These settings will only appear,
if the QoS function is enabled. In this entry menu, enter the
available bandwidth for the Downlink in full kilobits. On an interface to the Internet, this value corresponds to the bandwidth of
the Internet connection - on an ADSL access the Uplink bandwidth amounts to 768 kBit/s and on a 2-Megabit fixed connection
to 2048 kBit/s.
MTU Size: The MTU is the size (in bytes) of the largest
transmittable packet. MTU stands for Maximum Transfer Unit.
For connections, using the TCP/IP protocol, the data will be
subdivided into packets. A maximum size will be defined for
these packets. Packets larger than this value will be considered
too long for the connection and fragmented into smaller ones
before transmission. These data packets will be sent again. However, the performance can be limited, if the upper value is too
low.
148
Using the Security System
The following values are the defaults for the PPP over Ethernet
(PPPoE-DSL) connection: 1492 Byte.
6.
Confirm these settings by clicking Add.
The system will now check the address and netmask for semantic validity. After a successful check, the new interface will
appear in the Current Interface Status table. The interface is
not yet enabled (status light is red).
7.
Enable the interface by clicking the status light.
The interface is now enabled (status light shows green). The Oper
column will at first show that the interface is Down: the system
requires a short time to configure and load the settings. When the
message Up appears, the interface is fully operational.
149
Using the Security System
5.3.2.6.
PPTPoE/PPPoA-DSL Connections
This type of interface is required for DSL connections
using the PPP over ATM
protocol. To configure such a
connection, you will need an
unused Ethernet interface on
the security system as well
as an ADSL modem with an
Ethernet port. The connection
to
the
Internet
proceeds
through two separate connections
(see
graphic):
Between
the
security system and the ADSL modem, a
connection using the PPTP over Ethernet protocol is established. The ADSL
modem is, in turn, connected to the ISP
using
the
PPP
over
ATM
dialing
protocol.
The configuration will require the DSL
connection information, including username and password, provided by your
Internet Service Provider.
150
Using the Security System
Note:
The installation and specific settings required for DSL connections is
described in the DSL Network guidebook. Also note that, once the
DSL connection is activated, the security system will be connected to
your ISP 24 hours a day. You should therefore ensure that your ISP
bills on a flat-rate or bandwidth-based system rather than based on
connection time. The DSL Network guidebook is available at
http://docs.astaro.org.
Configuring PPTP over Ethernet (PPPoA-DSL):
1.
In the Network tab, open the Interfaces menu.
2.
Click the New button to open the Add Interface window.
3.
In the Name entry field, enter a descriptive name for the
interface.
4.
Use the Hardware drop-down menu to select a network card.
Tip:
For an external connection (e.g., to the Internet) choose the
card with Sys ID eth1.
You cannot choose a network card that has already been configured with a primary network address.
5.
Use the Type drop-down menu to select the PPTP over
Ethernet (PPPoA-DSL) connection interface type.
You will need the connection settings provided by your ISP to
configure the following settings.
Address: If you have not been assigned a static IP address by
your provider, keep the default Assigned by remote setting
here.
151
Using the Security System
If you have a static IP address, choose Static from the dropdown menu and enter the address in the entry field.
Default Gateway: You should probably keep the default setting
Assigned by remote. Other possible values are Static and
None.
Modem IP Address: Enter the IP address of your ADSL modem
here. This address will usually be provided by your ISP or the
modem hardware, and cannot be changed.
Example: 10.0.0.138 (with AonSpeed)
NIC IP Address: Enter the IP address of the network card on
the security system which is attached to the modem here. This
address must be in the same subnet as the modem.
Example: 10.0.0.140 (with AonSpeed)
NIC Netmask: Enter the network mask to use here.
Example: 255.255.255.0 (with AonSpeed)
Address to Ping: In order to test the connection between the
security system and the external network, you can enter an IP
address of a host on the Internet (e.g., the DNS server of your
ISP) here. The security system will send ping requests to this
host: if no answer is received, the connection will be broken.
Username: Enter the username, provided by your ISP.
Password: Enter the password, provided by your ISP.
Click Enable to open the Advanced options configuration
settings.
Uplink Failover on Interface this function will only be
displayed if the Assign by DHCP or Static is selected in the
Default Gateway drop-down menu.
You can configure a standby connection through a second interface. If the primary connection fails, the uplink will automatically
be set-up through the second interface.
152
Using the Security System
Note:
You need two separate Internet accesses and one additional
network card for the Uplink Failover on Interface function.
Please, note that the Security system only supports one DSLconnection. A standby connection for accessing the Internet can
therefore only consist, for example, of a fixed connection and a
DSL access.
Uplink Failover on Interface is by default disabled (Off). If
you wish to use this virtual interface as primary connection,
select Primary Interface from the drop-down menu. If this
interface shall contain the standby connection, select the
Backup Interface configuration.
Uplink Failover check IP: Once the Uplink Failover on
Interface function has been enabled, this entry field will be
displayed. Enter the IP-address of a host that replies to ICMPping-requests (e.g., the DNS server of your ISP). The security
system will send ping requests to this host: if no answer is
received, the backup-interface will be enabled by the failover. In
this entry field, there must always be an IP-address for the
failover.
QoS Status: In order to use Quality of Service (QoS)
bandwidth management on an interface, enable this option. To
enable the Quality of Service (QoS) module, select On from
the drop-down menu.
Important note:
For the bandwidth management Quality of Service (QoS) you
must define the values for Uplink Bandwidth (kbits) and
Downlink Bandwidth (kbits). These values are used as basis
for the bandwidth management system: incorrect values can
lead to poor management of the data flow. The Quality of
Service (QoS) function is described in chapter 5.5.1.
153
Using the Security System
Uplink Bandwidth (kbits): These settings will only appear, if
the QoS function is enabled. In this entry menu, enter the
available bandwidth for the Uplink in full kilobits. This value can
be determined either from the values of the upstream interface
or from the router. On an interface to the Internet, this value
corresponds to the bandwidth of the Internet connection - on an
ADSL access the Uplink bandwidth amounts to 128 kBit/s and on
a 2-Megabit fixed connection to 2048 kBit/s.
Downlink Bandwidth (kbits): These settings will only appear,
if the QoS function is enabled. In this entry menu, enter the
available bandwidth for the Downlink in full kilobits. On an
interface
to
the
Internet,
this
value
corresponds
to
the
bandwidth of the Internet connection - on an ADSL access the
Uplink bandwidth amounts to 768 kBit/s and on a 2-Megabit
fixed connection to 2048 kBit/s.
MTU Size: The MTU is the size (in bytes) of the largest
transmittable packet. MTU stands for Maximum Transfer Unit.
For connections, using the TCP/IP protocol, the data will be
subdivided into packets. A maximum size will be defined for
these packets. Packets larger than this value will be considered
too long for the connection and fragmented into smaller ones
before transmission. These data packets will be sent again.
However, the performance can be limited, if the upper value is
too low.
The following values are the defaults for the PPP over Ethernet
(PPPoA-DSL) connection: 1460 Byte.
6.
Confirm these settings by clicking Add.
The system will now check the address and netmask for
semantic validity. After a successful check, the new interface
will appear in the Current Interface Status table. The interface
is not yet enabled (status light is red)
7.
154
Enable the interface by clicking the status light.
Using the Security System
The interface is now enabled
(status light shows green).
The Oper column will at
first show that the interface
is Down: the system requires a short time to configure and load the settings. When the message Up appears, the
interface is fully operational.
5.3.3.
Routing
Every network-connected computer uses a routing table to determine
where outbound packets should be sent. The routing table contains
the
information
necessary
to
determine,
for
instance,
if
the
destination address is on the local network, or if traffic must be sent
via a router – and, if a router is to be used, the table details which
router is to be used for which network.
Static Routes
The security system will install static routing entries for directlyconnected networks by itself. Further routes, however, must be
manually entered. This is the case, for instance, when the local
network includes a router to be used for access to a specific network.
These routes, called static routes, contain information about how to
contact a non-directly connected network.
This menu allows you to define which network card or router should
be used to contact various external networks.
155
Using the Security System
Defining Static Routes:
1.
Under the Network tab, open the Routing menu.
2.
Click on the New button.
The Add Static Route window will open.
3.
In the Network drop-down menu, choose the network you wish
to define a route for.
The Network drop-down menu contains all static networks, as
well as those you have defined in the Networks and Interfaces
menus.
4.
In the Target drop-down menu, select the destination to which
packets should be forwarded.
Names in brackets are interfaces, while names without are
hosts or routers. Names without brackets are either hosts or
routers.
5.
Save your changes by clicking Save.
When a new route has been defined and saved, it will appear in the
Static Routes table. To remove an entry, click delete.
Kernel Routing Table
The Kernel Routing Table
will be displayed in a separate window. This window
shows all on the system
currently active routes. The
system will check each rule
in the order of the list, using
the first applicable route. By
default, the default routes
156
Using the Security System
associated with network cards are already entered, and are not
editable.
Clicking on the Show button opens the Kernel Routing Table window.
5.3.4.
NAT/Masquerading
5.3.4.1.
NAT
The
Network
Address
Translation (NAT) function translates one set of IP
addresses (usually private
ones)
to
addresses
in
another set (usually public).
NAT makes it possible for
computers on an internal
LAN to use private IP addresses, while still allowing
them to communicate – through the security system – with the public
Internet.
When a client sends an IP packet to the router, NAT translates the
sending address to a different, public IP address (from the address
space given by the Internet provider) before forwarding the packet to
the Internet. When a response packet is received, NAT translates the
public address into the original address and forwards it on to the
internal client. Depending on system resources, the NAT function can
handle arbitrarily large internal networks.
Destination Network Address Translation (DNAT) is a special
case of NAT whereby the destination addresses of packets are
translated. This is especially useful when an internal network uses
private IP addresses, but an administrator wishes to make some
services available to the public Internet.
157
Using the Security System
Important Note:
PPTP Roadwarrior Access is incompatible with DNAT.
Example:
Your
internal
network
uses
the
address
space
192.168.0.0/
255.255.255.0 and a web server running at IP address 192.168.0.20
port 80 should be available to Internet-based clients.
Because the 192.168 address space is private, the Internet-based
clients cannot send packets directly to the web server. It is, however,
possible for them to communicate with the external (public) address
of the security system. DNAT can, in this case, take packets
addressed to port 80 of the system’s address and forward them to the
internal web server.
Note:
The method of setting up a web server behind the Internet security
solution is described in the Web Server/DNAT guidebook. The Web
Server/DNAT guidebook is available at http://docs.astaro.org.
Source Network Address Translation (SNAT) is another special
case of NAT, and functions just as DNAT does, with the difference
that source addresses (rather than destination addresses) are
translated.
This is useful in complex networks where replies should be sent from
other network addresses.
Tip:
To build a simple translation system from an internal network to the
Internet, use the Masquerading function instead of SNAT.
158
Using the Security System
In contrast to Masquerading, which is dynamic, SNAT uses a static
address translation. That is, every internal address is translated to its
own externally visible IP address.
Note:
In order to forward port 443 (HTTPS) to an internal server, you must
first change the value of the WebAdmin TCP Port (e.g., 1443) for
WebAdmin in the System/WebAdmin Settings menu. This function
is described in chapter 5.1.8 in chapter General Settings.
Note:
Because translation occurs before Packet filtering, you must ensure
that appropriate rules are entered in the Packet Filter/Rules menu.
More information on setting packet filter rules can be found in
chapter 5.4 on page 179.
Defining NAT rules:
1.
In the Network tab, open the NAT/Masquerading menu.
2.
In the Name field, enter a descriptive name for this NAT rule.
3.
In the Rule type drop-down menu, select the DNAT/SNAT
function.
A window named Properties will open.
4.
In the Packets to match window, define which packets should
be translated.
At least one parameter in this window must be defined in order
to create a valid DNAT/SNAT rule. The setting No match means
that packets will not be matched on the basis of this parameter.
159
Using the Security System
Source address: Choose the original source address here: This
can be either a single host or an entire network.
Destination address: Choose the original destination address
here: This can be either a single host or an entire network.
Service: Choose the original service here: the service is defined
by source and destination ports as well as protocol used (e.g.,
TCP).
Note:
A service can only be redirected when the communicating
addresses are also redirected. In addition, a service can only be
redirected to another service when the two services use the
same protocol.
5.
Use the next drop-down menus to define how the packets should
be translated.
At least one parameter in this window must be defined in order
to create a valid DNAT/SNAT rule. If you redirect the original
address to an entire network, the addresses in that network will
be used one after another.
Change Source to (SNAT): Choose a new source address for
the translated packets. This can be either a single host or an
entire network.
Service source: This drop-down menu will only be shown when
you have chosen an address in the Change source to menu.
Only services with one source port can be used here.
Change Destination to (DNAT): Choose a new destination
address here. This can be either a single host or an entire
network.
Service destination: This drop-down menu will only be shown
when you have chosen an address in the Change destination
to menu.
6.
160
Save the settings by clicking Add.
Using the Security System
After successfully defining a rule, it will appear in the NAT Rules
table list. The further functions in the NAT table can now be used for
further customization.
Further Functions
Edit rule: Click edit to load the rule into the Edit NAT Rule window.
The rule can now be changed as desired.
Delete rule: Click Delete to remove a rule from the list.
5.3.4.2.
Masquerading
Masquerading is a special
case of SNAT, which allows
you to associate many internal (private) addresses with
one
external
(public)
ad-
dress. This allows you to hide
internal IP addresses and network information from the outside
network.
The differences between Masquerading and SNAT are:
•
Masquerading requires a source network. It will automatically
include all services (ports) on that network.
•
The translation only occurs when the packet is sent via the
supplied network card. The new source address will be that of the
interface.
Masquerading is intended to hide privately addressed LANs behind
one official (public) Internet address.
161
Using the Security System
Defining Masquerading rules:
To define masquerading rules, select which network should masquerade as which network card.
Normally, the external network card is
used.
Note:
In order for clients from the defined network to build a connection to
the Internet, the appropriate rules must be entered in the Packet
Filter/Rules
menu.
More information on setting packet filter rules can be found in
chapter 5.4 on page 179.
1.
In the Network tab, open the NAT/Masquerading menu.
2.
In the Name field, enter a descriptive name for this Masquerading Rule.
3.
Use the Rule type drop-down menu to select Masquerading.
A window named Properties will open.
4.
Use the Network drop-down menu to select a network.
5.
Use the Interface drop-down menu to select an interface.
6.
Save the settings by clicking Add.
After a masquerading rule has been defined and added, it will appear
in the NAT rules table. The further functions in the NAT table can
now be used for further customization.
Further Functions
Edit Masquerading rules : Click edit to load the rule into the Edit
NAT Rule window. The rule can now be changed as desired.
Deleting Masquerading rules: Click delete to remove a rule from
the list.
162
Using the Security System
5.3.4.3.
Load Balancing
The Load Balancing function allows you to balance
incoming connections (e.g.
SMTP or HTTP sessions)
across different servers behind the security system.
Example: In the enterprise’s
DMZ
sit
two
identical HTTP servers with
IP addresses 192.168.66.10 and 192.168.66.20. Load Balancing can
split incoming HTTP requests between the two servers evenly.
Before the load-balancing rule can be defined, the two HTTP servers
must be defined as networks (consisting of single hosts) in the
Definitions/Networks menu. Next, add both to a single network
group.
The procedures for adding networks and network groups are
described in chapters 5.2.1 and 103, respectively.
Once these definitions have been saved, the load balancing rules can
be defined.
Defining Load Balancing rules:
1.
In the Network tab, open the NAT/Masquerading menu.
2.
Enter a descriptive name for the load-balancing rule in the
Name entry field.
A window named Properties will open.
3.
Enter a descriptive name for the load-balancing rule in the
Name entry field.
4.
Use the Rule Type drop-down menu to select Load Balancing.
163
Using the Security System
5.
In the Pre-Balancing Target window, select the original
destination address and service.
Address or Hostname: Select the original destination address
here. This should usually be the external address of the security
system.
Service: Select the destination port (service) to be balanced.
6.
In the Post-Balancing Target Group drop-down menu, select
the new address. This will usually be a network group composed
of single hosts.
When the load-balancing rule has been defined and saved, it will
appear in the NAT rules table. The further functions in the NAT table
can now be used for further customization.
Editing Load Balancing rules: Click edit to load the rule into the
Edit NAT Rule window. The rule can now be changed as desired.
Deleting Load Balancing rules: Click delete to remove a rule from
the list.
164
Using the Security System
5.3.5.
DHCP Server
The
Dynamic
Host
Con-
figuration Protocol (DHCP)
automatically distributes addresses from a defined IP address
pool
to
client
com-
puters. It is designed to simplify network configuration on
large networks, and to prevent address conflicts. DHCP
distributes IP addresses, default
gateway
information,
and DNS configuration information to its clients.
In addition to simplifying the configuration of client computers and
allowing mobile computers to move painlessly between networks,
DHCP helps to localize and troubleshoot IP address-related problems,
as these are mostly issues with the configuration of the DHCP server
itself. It also allows for a more effective use of address space,
especially when not all computers will be active at the same time. as
addresses can be distributed as needed and re-used when unneeded.
Configuring the DHCP Server:
1.
In the Network tab, open the DHCP Server menu.
2.
In the Interface drop-down menu, select the interface from
which the IP addresses should be assigned to the clients.
3.
Click Enable next to Status to enable the function.
Another entry window will open.
4.
Use the Range Start and Range End menus to set the address
space from which IP addresses will be distributed.
165
Using the Security System
By default, the configured address area of the network card will
appear in the entry field.
The settings will take effect without further confirmation.
Assigning DNS Servers and Gateway IP Addresses:
You can transmit further parameters for the network configuration to
the clients. Such as the DNS Server Addresses and the Default
Gateway to be used by the clients. The security system itself will
usually fill both of these functions: in this case, you should enter the
internal address of the system in these entry fields.
The DNS Proxy is configured in the Proxies/DNS menu. Please see
chapter 5.6.2 on page 225 for a description of how to use the DNS
proxy.
NetBIOS networks can also use a WINS server for name resolution.
WINS stands for Windows Internet Name Service. WINS servers are
MS Windows NT servers with both the Microsoft TCP/IP stack and the
WINS server software installed. These servers act as a database
matching
computer
names
with
IP
addresses,
thus
allowing
computers using NetBIOS networking to take advantage of the TCP/IP
network.
1.
In the Network tab, open the DHCP Server menu.
2.
In the entry fields DNS Server 1 IP and DNS Server 2 IP,
enter the IP address of your name servers.
3.
In the Gateway IP entry field, enter the IP address of the
default gateway.
4.
If you wish to assign a WINS server, configure the following two
settings:
WINS Server IP: Enter the IP address of the WINS server here.
166
Using the Security System
WINS Node Type: Use the drop-down menu to choose which
kind of name resolution clients should use. If you choose Do not
set node type, the client will choose by itself which to use.
5.
Save your configuration by clicking Save.
Configuring Static Mappings:
This function allows you to ensure that specific computers are always
assigned the same IP address. To configure this function, you will
need to know the MAC (hardware) address of the client’s network
card.
Determining the MAC addresses of network cards is described on page
133.
1.
In the Network tab, open the DHCP Server menu.
2.
In the Static Mappings window, make the following settings:
MAC Address: In the MAC Address entry field, enter the MAC
address of the network card. The MAC address must be entered
as in the following example
Example: 00:04:76:16:EA:62
IP Address: Enter the IP address into this entry field. The
address must be within the range specified by the Range Start
and Range End options.
3.
Save the settings by clicking Add.
The static address mapping will appear in the Static Mapping Table.
To remove an entry from this table, click delete.
167
Using the Security System
Current IP Leasing Table
The Current IP Leasing table shows all current IP address mappings. If more than one entry is shown for the same IP address, only
the last-listed one is valid. This table will only be shown when there
are entries in it.
168
Using the Security System
5.3.6.
PPTP VPN
Point-to-Point Tunneling Protocol (PPTP) allows single Internetbased hosts to access internal network services through an encrypted
tunnel. PPTP is easy to set-up, and requires on Microsoft Windows
systems no special client software.
PPTP is included with versions of Microsoft Windows starting with
Windows 95. In order to use PPTP with this security system, the
client computer must support the MSCHAPv2 authentication protocol.
Windows 95 and 98 users must apply an update to their systems in
order to support this protocol. The update is available from Microsoft
at:
http://support.microsoft.com/support/kb/articles/Q191/5/40.ASP
Select the VPN Update and, if you use Windows 95, also the RAS
Update.
PPTP VPN Access
This window allows you to
enable or disable PPTP VPN
access by clicking the Enable/Disable button.
Logging: This drop-down menu allows you to choose how detailed
the information recorded in the PPTP Logs should be. The Extensive
setting should be used when you are using the Live Log to debug
connection problems. When you start the connection, you can view
the process in real time.
The PPTP Live Log is in the Local Logs/Browse menu.
Encryption: This drop-down menu allows you to choose between
encryption strengths (40-bit or 128-bit). Note that, in contrast to
Windows 98 and Windows ME, Windows 2000 does not come with 128
bit encryption installed: to use this kind of connection, the High
169
Using the Security System
Encryption Pack or Service Pack 2 must be installed. SP2 cannot
be uninstalled later.
Security Note:
You should always set Encryption to Strong (128-bit) except
when your network includes endpoints, which cannot support
this.
Authentication:
Use
this
drop-down
menu
to
select
an
authentication method If you have defined a RADIUS server in the
System/User
Authentication
menu,
you
can
use
RADIUS
authentication here as well.
The configuration of the Microsoft IAS RADIUS server and the
configuration of RADIUS within WebAdmin is described in chapter
5.1.7 on page 71.
The PPTP Live Log provides a list of important events, including
error messages, related to the PPTP service. The Logging menu can
be used to select which events are logged.
PPTP IP Pool
This menu is used to define
which
IP
addresses
PPTP
hosts should be assigned.
The default settings assign
addresses from the private
IP space 10.x.x.x. This network is called the PPTP Pool, and can be
used in all of the other security system configuration options. If you
wish to use a different network, simply change the definition of the
PPTP Pool, or assign another defined network as PPTP Pool here.
PPTP users are defined in the Definitions/Users menu. It is also
possible to assign specific users to specific IP addresses. These
addresses do not need to be part of the defined PPTP pool. To use
170
Using the Security System
these addresses in other parts of the system configuration, such as
the packet filter, they must be defined as single hosts (i.e., networks
with netmask 255.255.255.255) or as a part of a larger network.
Note:
If you use private IP addresses for the PPTP pool and you wish
PPTP-connected computers to be allowed to access the Internet,
appropriate Masquerading or NAT rules must be in place.
PPTP Client Parameters
This window allows you to
define name servers (DNS
and WINS) and the name
service
domain,
which
should be assigned to hosts
during the connection establishment.
Connections with MS Windows 2000:
The following example shows how to configure a PPTP VPN connection
on a Windows 2000 host.
1.
Under the Network tab, open the PPTP VPN Access menu.
2.
In the PPTP VPN Access window, enable the system by clicking
Enable.
The status light will show green and the menu will open.
3.
In the PPTP VPN Access window, make the settings for the
network access:
Logging: Keep the setting Normal.
171
Using the Security System
Encryption: In the drop-down menu, select the encryption type.
The available options are weak (40 bit) and strong (128 bit).
Note that, in contrast to Windows 98 and Windows ME, Windows
2000 does not come with 128 bit encryption installed:
to use this kind of connection, the High Encryption Pack or
Service Pack 2 must be installed. SP2 cannot be uninstalled
later.
The
selected
encryption
strength
will
take
effect
immediately.
Important Note:
Both sides of the connection must use the same encryption
strength. If WebAdmin is set to use 40-bit encryption, and the
MS Windows 2000 client is set to use 128-bit encryption,
Windows will incorrectly report that the connection has been
established.
Authentication: Use the drop-down menu to select a service.
4.
Now define which IP addresses should be assigned to the hosts
when connecting. In the PPTP IP Pool window, use the Network drop-down menu to select a network. The chosen network
will be used immediately.
The PPTP Pool network is selected by default.
The IP address, network mask, and number of free addresses
will appear below the drop-down box.
Users will be assigned an address from this range automatically.
5.
In the PPTP Client Parameters window, DNS and WINS
servers for PPTP clients can be defined. Two servers may be
defined for each.
Client DNS servers: Enter the IP addresses of the DNS servers
to use.
Client WINS Servers: Enter the IP addresses of the Windows
name servers to use.
172
Using the Security System
Client domain: Enter the DNS domain that the client should
append to DNS requests.
6.
Save your configuration by clicking Save.
The rest of the configuration takes place on the user’s machine. This
will require the IP address of the server, as well as a valid username
and password. These should be supplied by the security system
administrator.
1.
In Microsoft Windows 2000, open the Start/Settings/Network
and Dialup Connections menu.
2.
Click the Make New Connection icon.
The Network Connection Wizard will open.
Then click on the Next button.
3.
Select the following option: Connect to a private network
through the Internet.
Then click on the Next button.
4.
If you have a permanent connection to the Internet, select the
following option Do not dial the initial connection.
Then click on the Next button.
Otherwise, select the Dial other connections first option and
select your provider from the selection menu. These settings can
be changed later in the Properties dialog box.
5.
In the Destination address entry field, enter the IP address of
the server.
Then click on the Next button.
6.
In the Connection Availability window, select whether the
connection should be available to all local users, or just this
account.
Then click on the Next button.
173
Using the Security System
7.
In the next text entry field, enter a descriptive name for this
PPTP connection.
Then click on the Next button.
8.
In the Start/Settings/Network and Dialup Connections, a
right-click on the new icon will allow you to open the Properties
window and configure further options:
General: This allows you to change the hostname or destination
address of the connection. In the Connect First window, select
any network connections that need to be established before
setting up the PPTP session.
Options: The dial and redial options can be defined here.
Security: Choose the Advanced (Custom Settings) option.
Next click the Settings button. Leave these settings as they are.
Network: In the Type of VPN Server I am calling menu,
select the Point-to-Point-Tunneling Protocol (PPTP) option.
Sharing: This menu allows you to share the PPTP connection
with other computers on the local network.
To start the PPTP connection, simply click the new icon in the
Start/Settings/Network and Dialup Connections menu.
Further
information
administrator.
174
is
usually
available
from
the
network
Using the Security System
5.3.7.
Accounting
When the Accounting function is enabled, the security
system will track all transmitted
data
and
compile
statistics about it. The accounting menu allows you
to
select
which
network
cards should be monitored. You can download the data from the Log
Files/Accounting menu, or view daily reports in the Reporting/
Accounting menu.
Important Note:
In the normal case, you should only enable Accounting on one
network card, because, if more than one card is monitored, data
forwarded from one monitored interface to another monitored one
will be counted twice.
If you use Masquerading, you should probably use Accounting on
the internal interface. Otherwise, data packets dropped by the
security system filters will be included, and will appear to come from
the wrong interface.
It is also possible to exclude certain Hosts or Networks from the
accounting records. After installation, all networks are included in
accounting records.
It may be useful to block certain hosts or networks from accounting
data, for instance when a DMZ host only communicates with internal
systems, but you are only interested in collecting accounting data
for outbound traffic. ince it might only be used for internal means, it
might not be useful to consider its traffic data.
In the Reporting/Accounting menu, you can monitor the collected
accounting data and edit accounting rules.
175
Using the Security System
Important Note:
Do not use accounting on
network interfaces. Doing so may
overload the system.
Configuring Traffic Accounting:
1.
In the Network tab, open the Accounting menu.
2.
Enable the function by clicking the Enable button.
The status light will show green and another entry window will
open.
3.
In the Interfaces selection field, choose the network cards.
Please see chapter 4.3.2 on page 36 for a description of how to
use selection fields.
4.
Use the Ignored Networks selection menu to choose which
networks to ignore.
The settings in the Traffic Accounting menu will immediately be
enabled.
176
Using the Security System
5.3.8.
Ping Check
Ping allows you to test the
connection with a remote
host on the IP level. Please
note that these tools require
that the ICMP on firewall option under the Packet Filter/ICMP
menu be enabled. Ping sends an ICMP Echo Packet to the remote
machine. When this packet is received by the remote machine, its
TCP/IP stack will generate an ICMP Reply Packet and send it back.
This allows you to test that IP-level connectivity with the remote
machine.
Ping Check also allows you to check the connection with a host by
entering the DNS hostname. In order to do that, DNS Proxy must be
enabled in the Proxies/ DNS menu.
Note:
•
Ping will not work unless ICMP on firewall (in the Packet
Filter/ICMP menu) is activated.
•
Name Resolution will not work unless DNS Proxy (in the
Proxies/DNS menu) is activated.
177
Using the Security System
Using Ping:
1.
Under the Network tab, open the Ping Check menu.
2.
Use the Ping Host drop-down menu to select a network card.
If this is an interface with a host, configured in one of the menus
Interfaces or Networks, you can select it directly from the
drop-down menu.
(Example: Internal (Address) for the internal network card on
the security system).
For another host in the network, select the setting Custom
Hostname/IP Address from the drop-down menu.
3.
In the Hostname /IP Address entry field, enter the IP address
or hostname.
4.
178
Click Start to begin the test connection.
Using the Security System
5.4. Intrusion Protection
The Intrusion Protection System (IPS) recognizes attacks with
the help of a signature-based Intrusion Detection set of rules. The
system analyzes the complete traffic and automatically blocks attacks
before they can reach the network.
The existing set of rules and/or IPS attack signatures are updated
through the Pattern Up2Date function. New IPS attack signatures
will automatically be imported as IPS rule to the IPS set of rules.
5.4.1.
Settings
Global Settings
In
the
window,
configure
the basic settings for the
Intrusion Protection System (IPS) option.
Status: Clicking on the Enable button enables the option.
Local Networks: From the selection field select those networks that
should be monitored by the Intrusion Protection System (IPS). If no
specific network is selected, the complete data traffic will be
monitored.
Portscan Detection
The
Portscan
Detection
(PSD) feature allows you to
detect possible attacks from unauthorized users. Portscans are used
by hackers to probe secured systems for available services: In order
to intrude into a system, or to start a Denial-of-Service (DoS)
attack, attackers need information on network services. If this
179
Using the Security System
information is available, attackers might make use of the security
deficiencies of these services. Network services using the TCP and
UDP Internet protocols, can be accessed via special ports and this
port assignment is generally known, for example the SMTP service is
generally assigned to the TCP Port 25. The ports, used by the services
are referred to as open, since it is possible, to establish a connection
to them. Whereas unused ports are referred to as closed, every
attempt to connect with them fails. The attacker tries to find the open
ports with the help of a particular software tool, i.e. the Port Scanner.
This program tries to connect with several ports on the destination
computer. If it is successful, the tool displays the relevant ports as
open and the attacker has the necessary information, showing him
which network services are available on the destination computer.
The following is an example of the information returned by a port
scanner:
Interesting ports on (10.250.0.114):
(The 1538 ports scanned but not shown below are
in state: closed)
Port
State
Service
25/tcp
open smtp
135/tcp
open loc-serve
139/tcp
filtered netbios-ssn
445/tcp
open Microsoft-ds
1032/tcp
open iad3
Since 65535 ports are available for the TCP and UDP Internet
protocols, the ports are scanned at very short intervals. When the
firewall detects an unusually large number of attempts to connect to
services, especially when these attempts come from the same source
address, this is almost certainly due to a portscan.
PSD watches for such scans and immediately informs the administrator via e-mail when one is detected. The administrator can also
decide what further measures should be taken in response to the
180
Using the Security System
scan. The e-mail address of the administrator can be configured in the
System/Settings menu.
Security Note:
The administrator should take special care that all systems have
the most recent security patches installed.
The Up2Date service, which updates the security system itself,
is detailed in chapter 5.1.3 on page 54.
Notification Levels
If the Intrusion Protection System (IPS) detects
IPS
attack
signatures
or
prevents an intrusion, the
system will send a message to the administrator. The e-mail address
of the administrator can be configured in the System/Settings
menu.
Detected Packets: Use this drop-down menu to select the severity
level from which on a warning should be sent (Intrusion Detection).
•
All levels: For each level of risk.
•
High and medium severity: for high and medium levels of risk.
•
High severity only: only for high risk levels.
•
None: No warning will be sent.
Blocked Packets: Use this drop-down menu to select the level of
risk, from which on a warning should be sent (Intrusion Prevention).
•
All levels: For each level of risk.
•
High and medium severity: for high and medium levels of risk.
•
High severity only: only for high risk levels.
•
None: No warning will be sent.
181
Using the Security System
5.4.2.
Rules
The Rules menu contains the Intrusion Protection System set of
rules (IPS). The already existing base set of rules with the IPS attack
signatures can be updated through the Pattern Up2Date function, if
desired. New IPS attack signatures will automatically be imported as
IPS rule to the IPS rules table.
The Pattern Up2Date function is described in further detail in
chapter 5.1.3 on page 54.
IPS Rules Overview
The overview contains all IPS sets of rules.
The functions in the overview from the left to the right:
/
: Clicking on the status light enables the IPS set of rules.
/
: The IPS rule can be configured as alarm rule (Intrusion
Detection) or as blocking rule (Intrusion Prevention). Clicking on the
icon switches the application of the IPS rules in this group.
: Clicking on the folder icon opens the sub-tab with all protocols of
this group.
By clicking again on the icon, you will get back to the overview. The
182
Using the Security System
additional functions in the sub-tab are described in the „IPS Rules
Sub-tab“ section.
Group: The name of the IPS group of rules is displayed in this
column. The groups are put in alphabetical order according to this
name. Clicking in the header automatically displays the groups in deor increasing alphabetical order.
Hits: This column displays, how often a rule from the group became
active.
Info: This column provides short information on this IPS rule group.
The IPS Rule Sub-tab
All IPS rules of a group are listed in this sub-tab. The sub-group can
be opened in the overview by clicking on the folder icon ( ).
The functions in the sub-tab from the left to the right:
/
: Clicking on the status light enables the IPS rule.
/
: The IPS rule can be configured as ----/ alarm rule
(Intrusion Detection) or as ----/blocking rule (Intrusion Prevention).
183
Using the Security System
Clicking on the icon switches the application of the IPS rule in this
group.
: Return to the overview by clicking on the folder icon.
Group: The name of the IPS group of rules is displayed in this
column.
Hits: This column displays, how often a rule from the group became
active.
Info: The first line provides short information on this IPS rule group.
You can obtain detailed information on the IPS rules by clicking on the
correspondent icon with the mouse.
: This window presents the parameters of this as Low Layer
Information.
: Clicking on the icon connects you to the correspondent link in
the Internet. The Website contains further information on the IPS
rule. This information is compiled in projects such as Common
Vulnerabilities and Exposures (CVE) and published in the Internet.
Setting an IPS rule:
You can add your own IPS rules to the set of rules. The rules are
based on the syntax of the Snort Open Source ID System. Manually
configured IPS rules are always locally imported to an IPS set of
rules. For more information please see the following Internet address:
http://www.snort.org.
1.
Under the Intrusion Protection tab, open the Rules menu.
2.
Click on the button.
The entry window will open.
184
Using the Security System
3.
Make the following settings:
Description: Enter a description of the rule in the entry field.
Example: Large ICMP packet
Selector: Enter the selection parameters for the IPS rule in the
Snort syntax in the entry field.
Example: icmp $EXTERNAL_NET any -> $HOME_NET any
Filter: Enter the real identification parameter for the IPS rule in
Snort syntax in the entry field. Please make sure that the entry
ends with a ;-sign.
Example: dsize: >800;
4.
Save your configuration by clicking Add local Rule.
The new IPS rule is always locally imported to an IPS set of rules.
The rule is immediately enabled (status light shows green).
185
Using the Security System
5.4.3.
Advanced
This menu allows you, to
configure additional settings
for the Intrusion Protection System (IPS). This
should, however, only be
done by experienced users.
Policy and Exclusions
Policy: From this drop-down menu select the security policy that the
Intrusion Protection System should use, if a blocking rule detects an
IPS attack signature.
•
Drop silently: The data packet will only be blocked.
•
Terminate connection: A TCP Reset and/or ICMP Unreachable
(for UDP) packet will be sent to both communication partners and
the connection will be terminated.
IPS Network Exclusions: Specific connections between the networks of the Intrusion Protection System (IPS) can be excluded in this
selection menu.
The connections will be listed in a table below the selection menu.
Clicking the trash can icon (--) deletes the defined connection from
the table.
186
Using the Security System
Performance Tuning
The performance of the Intrusion Prevention System (IPS) can be
enhanced through the settings in this window, in which the servers
and ports are defined. The correspondent IPS rules will only be used
for the configured servers and ports.
The server must first be added as host in the Definitions/Networks
menu. For more information on adding hosts, please refer to chapter
5.2.1 on page 103.
Note:
If you don’t configure a server in this window, the Intrusion
Protection System (IPS) will monitor the complete data traffic
according to the settings in the Global Settings window.
HTTP Service: In this drop-down menu select the target port for the
HTTP data traffic, by selecting a Service. In the Definitions/
Services menu, you can change or add a Service, if necessary. The
added service will only use the target port number. In the case of a
port range, only the first and last port will be used.
Example: In a port range 80:8080 the HTTP rule will be used for the
target port 80 and 8080.
HTTP Servers: Select the HTTP servers in this selection field.
DNS Servers: Select the DNS servers in this selection field.
SMTP Servers: Select the SMTP servers in this selection field.
SQL Servers: Select the SQL servers in this selection field.
Telnet Servers: Select the Telnet servers in this selection field.
187
Using the Security System
5.5. Packet Filter
The Packet Filter is the central part of the firewall. In the Rules
menu you define the allowed data traffic between the networks and
hosts in the form of Packet filter rules. You can also define specific
packets, which will never be allowed to pass through the firewall. The
packet filter management is done in the Rules table.
The tools in the ICMP menu allow you to check the network
connections and functions of the security system. The additional and
reporting functions are available in the Advanced menu.
5.5.1.
Rules
The Rules menu allows you
to define packet filter sets of
rules. These rules are defined with the help of the
network and service definitions.
In general, there are two basic kinds of packet filtering policy:
•
Default allow – the rules explicitly define which packets are
blocked; all others are allowed.
•
Default deny– the rules explicitly define which packets are allowed;
all others are dropped.
This security system uses a Block all packets policy, as this policy is
inherently much more secure. This policy requires you to define
explicitly, which IP packets will be allowed to pass the filter. All other
packets will be blocked and – depending on the action chosen –
displayed in the Packet Filter Live Log. The Packet Filter Live Log
is contained in the menu Packet Filter/Advanced.
188
Using the Security System
Example:
Network A is a subset of network B. Rule 1 allows SMTP traffic
destined for Network A. Rule 2 blocks SMTP for network B. Result:
Only SMTP traffic for network A will be allowed. SMTP packets from
the rest of network B IP addresses will be blocked.
A packet filter rule is defined by the source address (Source), a
service (Service), the destination address (Destination) and a
Response (Action).
The following values can be chosen as source and target addresses.
Please see the corresponding chapters of this for a more detailed
explanation of how to configure and manage these targets.
•
A Network – networks are defined in the Definitions/Networks
menu.
•
A Network Group – network groups are defined in the Definitions/Network menu.
•
An Interface network – logical networks are defined automatically
by the system when configuring a new network card or interface.
Interfaces can be configured in the Network/Interfaces menu.
•
An IPSec Remote Key Object (IPSec User Group) – the IPSec
User groups are defined in the Definitions/Networks menu. This
address or port range is required when configuring packet filter
rules for IPSec Road Warrior Endpoints.
A new defined packet filter rule is initially disabled, when it is added
to the table. Active rules are applied in the given order, ending with
the first matching rule. The order of this process will be displayed in
the table through the Position number (second column from the
left). If you re-sort the rules table later, for example according to the
source address please, note that the rules won't be displayed in the
order in which the system processes the rules. If, however, you
change the numerical rule order via the Position number, the
processing order will change correspondingly. In our example, if rule
189
Using the Security System
2 were moved to be before rule 1, all SMTP traffic for both networks
would be blocked. Be very careful when defining rules and their order,
as this will determine the security of your firewall.
Important Note:
When one filter rule applies, all other rules will be ignored! The
sequence of rules is thus very important. Never place a rule like Any
(Source) – Any (Service) – Any (Destination) – Allow (Action) at
the top of the rule set.
Setting Packet Filter Rules:
1.
Under the Packet Filter tab, open the Rules menu.
2.
Click on the New button.
The entry window will open.
3.
Make the following settings:
Position: Define the line of the table, in which the packet filter
rule will be entered. It is possible, to change the sequence of the
packet filter rules later. By default, the rule is placed at the end
(To Bottom) of the rules table.
Group: For a smooth management of the set of rules, the
packet filter rules can be grouped together in one group. This
does not influence the way, in which a rule will be processed
within the set of rules.
190
Using the Security System
For the first rule, no group can be selected from the drop-down
menu yet. New groups are defined in the set of rules table.
Source: In the drop-down menu, select the source address of
the data packets. The Any setting applies to all IP-addresses,
regardless of whether these are publicly assigned IP-addresses
or private IP-addresses according to RFC1918.
Service: Use the drop-down menu to select a service.
This list includes all the pre-defined services included in the
Security system, as well as the ones that you defined yourself.
This allows you to define precisely which traffic should be
allowed. The Any setting represents here all combinations of
protocols and source and/or destination ports.
Destination: In the drop-down menu, select the source address
of the data packets.
The Any setting applies to all IP-addresses, regardless of
whether these are publicly assigned IP-addresses or private IPaddresses according to RFC1918.
In the Action drop-down menu, select the action to execute if a
data packet complies with the settings for Source, Service und
Destination: In connection with this action, the priority for the
Quality of Service (Qos) function is also configured here.
Important Note:
In order to enable the priorities high priority and low priority,
you must select the respective interface for the QoS function in
the Network/Interfaces menu and also define the values
Uplink
Bandwidth
(kbits)
and
Downlink
Bandwidth
(kbits).
Allow: All packets, complying with this rule are allowed to
pass.
191
Using the Security System
Allow (high priority): All packets, complying with this rule
are allowed to pass. In addition, this data traffic gets a higher
priority if the Uplink is overloaded.
Allow (low priority): All packets, complying with this rule are
allowed to pass through. In addition, this data traffic gets a
lower priority if the Uplink is overloaded.
Drop: All packets matching this rule are blocked.
Reject: All packets, complying with this rule are denied. In
addition, the firewall will send an ICMP error to the sending
computer.
Log: Any violation of the rule will be reported in the Packet
Filter Live Log. This action is enabled by clicking on the check
box.
For such filter violations, which take place very often, and
which are not particularly security-relevant and only reduce the
readability of the Packet Filter Live Log (e.g. Windows
NetBIOS broadcasts), we recommend not to enable the Log
function.
Comment: In this entry field you can optionally enter a
comment on a rule.
4.
Save your configuration by clicking Add Definition.
If the definition was successful, the new Packet filter rule will
be added to the rule table in a deactivated state, marked by the
red status light.
5.
Activate the Packet filter rule by clicking the status light.
After the rule is added to the table, further options are available for
managing and editing rules in the rules table.
192
Using the Security System
Note:
By default, new rules are added in an inactive state in the table. The
rule will only become effective when it is set to be active. See
Activating/deactivating rules.
The Rules Table
Each packet filter rule will be displayed in the table through a
separate line: The different settings will either be displayed as alphanumeric signs or as symbols. While all settings with alphanumeric
signs can be edited by clicking on the correspondent field, this is not
possible with all symbol displays.
The following table explains all symbols from the rules table:
The Symbols
Icon
Spalte
Anzeige/Einstellung
Trash can
Status light
Packet filter rule is disabled
Status light
Packet filter rule is enabled
Source/Destination
Host
Source/Destination
Network
Source/Destination
Network group
Source/Destination
DNS Hostname
Source/Destination
IPSec User Group
Action
Allow
Action
Allow (high priority)
193
Using the Security System
Icon
Spalte
Anzeige/Einstellung
Action
Allow (low priority)
Action
Drop
Action
Reject
Log
Log disabled
Log
Log enabled
Adding/editing groups: Clicking in the field in the Group column
opens an entry window. Clicking on the Save button saves your
changes.
To cancel this service click on the Cancel button.
Enabling/Disabling Packet filter rules: The status light in the
fourth column shows the rule status. Clicking the status light toggles
the state between active (green light) and inactive (red light).
Deactivated rules remain in the database, but have no effect on
firewall behavior.
Edit rules: Clicking on the correspondent setting will open an entry
window. The rule can then be modified. Click Save to save your
changes.
In order to interrupt this process, click on the Cancel button.
Re-order rules: The order of the rules in the table determines the
behavior of the firewall; having the correct order is essential for
secure operation. By clicking the position number, you can adjust the
order to suit your needs. In the drop-down menu select the Position,
to which you wish to place the packet filter rule and confirm your
settings by clicking on the Save button.
Delete rules: Click the trash can icon to delete a rule from the table.
Sorting the rules table: By clicking on the column headers, you can
sort the table: for instance, to sort the rules by sender address, click
194
Using the Security System
Source. To return to the precedence-based sorting Matching, click
the column with the position numbers.
Filters
The Filters function allows you to filter Packet Filter Rules by specific
attributes. This function enhances the management of huge networks
with extensive sets of rules, since rules of a specific type can be
presented in a concise way.
Filtering rules:
1.
Click on the Filters button.
2.
The entry window will open.
3.
Enter the filter attributes in the fields. Not all attributes must be
defined.
Group: If you want to filter the rules of a specific group, select
them from the drop-down menu.
State: This drop-down menu allows you to filter rules by a
specific status.
Source: This drop-down menu allows you to filter rules by a
specific source address.
Service: If you want to filter rules by a specific service, select it
from the drop-down menu.
Action: This drop-down menu allows you to filter rules by a
specific action.
Destination Port: This drop-down menu allows you to filter
rules by a specific destination address.
Log: This drop-down menu allows you to filter logged rules.
Comment: If you want to filter services by specific comments,
enter the expressions in the entry menu.
4.
To start the filter click on the Apply Filters button.
195
Using the Security System
Only the filtered packet filter rules will be displayed then. When the
menu is closed, the complete set of rules will be displayed again.
Quality of Service (QoS)
Internet Service Providers usually measure the
service they provide in terms of bandwidth,
measured in kBit/s. If a server tries to cross
the saturation boundary – if it tries to send
more information than the link can carry – the
communication can either slow to a crawl or be
dropped altogether.
The graphic at left, for example, shows a
network with a web server and an FTP server.
Both servers share a 2Mbit uplink to the
Internet. Due to the protocols, TCP based applications (e.g. FTP)
always use the full bandwidth. It might thus happen that not enough
bandwidth is available for the Web Server.
The
Quality-of-Service-(QoS)
function
allows
you
to
assign
different priorities to the connections, if the Uplink is overloaded.
These priorities are defined in the packet filter rules through the
Allow, Allow (high priority) and Allow (low priority) actions.
Important Note:
In order to enable the priorities high priority and low priority, you
must select the respective interface for the QoS function in the
Network/Interfaces menu and also define the values Uplink
Bandwidth (kbits) and Downlink Bandwidth (kbits).
196
Using the Security System
In order to assign the same bandwidth to the connection with the web
server, as shown in the example, as the one for the connection with
the FTP server, both packet filter rules must be set to the same
Action:
1. Rule for data packets from the web server:
Source: web server
Service: HTTP
To (Server): Internet
Weight: Allow (high priority)
2. Rule for data packets from the FTP server:
Source: FTP server
Service: FTP
Destination: Internet
Action: Allow (high priority)
If the Uplink is only used by the data packets of these two servers,
each connection receives one half of the bandwidth (1MBit/s) in the
Worst Case. The High Priority setting becomes only relevant, if a
third data connection is established. All connections with a lower
priority, Allow or Allow (low priority), will be treated with a lower
ranking.
197
Using the Security System
Additional Functions and Settings
Internet-wide Broadcast:
In order to drop IP broadcast packets, first define the broadcast
address in the Definitions/Networks menu in the form of a new
network. Next, install the appropriate packet filter rule and activate it.
1.
Under Definitions, open the Networks menu and define the
following network:
Name: Broadcast32
Type: Host
IP Address: 255.255.255.255
Comment (optional): Enter a comment.
2.
Confirm the entries by clicking Add Definition.
3.
Under Packet Filter, open the Rules menu and enter the
following rule:
Source: Any
Service: Any
Destination: Broadcast32
Action: Drop
Comment (optional): Enter a comment.
4.
198
Confirm the entries by clicking Add Definition.
Using the Security System
Segment-wide Broadcast:
For each network card configured in the Interfaces menu, the system
automatically defines a network named NAME (Broadcast).
For more information, please see the Current Interface Status
section of chapter 5.3.2 on page 119.
1.
Under Packet Filter, open the Rules menu and enter the
following rule:
Source: Any
Service: Any
Destination: Select the broadcast network for the relevant
interface here.
Example: NAME (Broadcast)
Action: Drop
Comment (optional): Enter a comment.
2.
Confirm the entries by clicking Add Definition.
199
Using the Security System
5.5.2.
ICMP
ICMP Settings
This menu is used to configure the settings for Internet Control Message Protocol (ICMP) packets:
ICMP is used for testing network connectivity
and troubleshooting
network problems.
Note:
More information on ICMP can also be found in the Ping and
Traceroute sections.
ICMP on firewall and ICMP forwarding apply to all IP addresses
(Any). When ICMP on firewall is activated (green status light), all
IP addresses can ping the firewall; when ICMP forwarding is
enabled, computers on the external network can ping hosts behind
the firewall. Pings to single IP addresses cannot then be blocked with
packet filter rules.
Important Note:
Settings configured here take precedence over rules configured in the
packet filter rules table.
When the ICMP settings are disabled, packet filter rules can be used
to allow specific IP addresses or networks to ping the firewall or
internal network.
ICMP Forwarding: This allows you to forward all ICMP packets
behind the firewall. This means, that all IPs in the local network and
in all connected DMZs can be pinged.
Click the Enable button to enable the function (status light shows
green).
200
Using the Security System
Important Note:
If you wish to disable ICMP forwarding, you must ensure that the
Packet Filter/Rules menu does not contain a rule of the form Any
(Source) – Any (Service) – Any (Destination) – Allow (Action).
Otherwise ICMP forwarding will remain active irrespective of the
setting here.
ICMP on Firewall: The firewall directly receives and forwards all
ICMP packets. This is enabled by default /status light shows green).
Click the Disable button to change disable the function (status light
shows red).
Note:
ICMP on firewall must be activated to use the Ping action. The
action is described in more detail in the Network/Ping Check menu
and is described in chapter 5.3.8 on page 177.
Log ICMP Redirects: ICMP Redirects are sent from one router to
the other, in order to find a better route for a destination. Router then
change their routing tables and forward the following packets to the
same destination on the supposed better route.
This function logs the ICMP Redirects. Clicking on the Enable button
enables the function (status light is green).
Traceroute Settings
Traceroute is a tool used to
check and troubleshoot network routing. This tool can
resolve the path to an IP
address. Traceroute lists the IP addresses of the routers that had
been used to transport the sent packet. Should the packet path not
be reported within a certain time interval, traceroute will report a star
(*) instead of the IP address. After a certain number of failures, the
201
Using the Security System
test will end.
An interruption of the test can have any number of causes, notably a
packet filter along the network path that blocks traceroute packets.
This window shows advanced options related to ICMP Traceroute.
The settings here can also open the UDP ports UNIX Traceroute
uses.
Firewall is Traceroute visible: When this function is enabled, the
firewall will respond to Traceroute packets.
Click the Enable button to enable the function (status light shows
green).
Firewall forwards Traceroute: When this function is enabled, the
firewall will forward Traceroute packets.
Click the Enable button to enable the function (status light shows
green).
Note:
These two functions, Firewall is Traceroute visible and Firewall
forwards Trace route, are probably only useful when both are
enabled.
Traceroute from Firewall: The Traceroute command can be used
on the firewall.
Click the Enable button to enable the function (status light shows
green).
202
Using the Security System
Ping Settings
This window contains configuration options specific
to ICMP Ping.
Further information about
Ping can be found in chapter 5.3.8 on page 177.
Firewall is ping visible: When this function is enabled, the firewall
will respond to Ping packets. Click the Enable button to enable the
function (status light shows green).
Firewall forwards Ping: When this function is enabled, the firewall
will forward Ping packets. Click the Enable button to enable the
function (status light shows green).
Ping from Firewall: The Ping command can be used on the firewall.
Click the Enable button to enable the function (status light shows
green).
5.5.3.
Advanced
Connection Tracking Helpers
The
Stateful
Inspection
Packet Filter and the NAT
function are provided by the
iptables module in the Netfilter sub-system. All connections, operated with the packet filter, will
be tracked by the Conntrack module: this is referred to as Connection Tracking.
Some protocols, such as FTP or IRC require several communication
channels, which cannot be connected through port numbers. In order
to use these protocols with the Packet filter, or to replace an address
through NAT, the Connection Tracking Helpers are required.
203
Using the Security System
Helpers are structures, referring to so-called Conntrack Helpers.
Generally speaking these are additional Kernel modules that help the
Conntrack module to recognize existing connections.
For FTP data connections, a FTP Conntrack helper, for example, is
necessary. It recognizes the data connections, belonging to the
control connection (normally TCP Port 21), which can have any
destination port and adds the respective expect structures to the
expect list.
The following protocols are supported. By default, all Helper modules
are loaded:
•
FTP
•
H323
•
IRC (for DCC)
•
MMS (Microsoft Media Streaming)
•
PPTP
Loading Helper Modules: By default, all
Helper modules are
loaded.
The helper modules are loaded and deleted in the selection field.
A description of how to use the selection fields can be found in
chapter 4.3.2 on page 36.
SYN Rate Limiter
Denial-of-Service
(DoS)
on
attacks
servers,
shall
deny the service access to
legitimate users. In the simplest case, the attacker overloads the
server with useless packets, to overload its performance. Since a
large bandwidth is required for such attacks, more and more
204
Using the Security System
attackers start using so-called SYN-Flood attacks, which don't aim at
overloading the bandwidth, but at blocking the system resources. For
this purpose, they send so-called SYN packets to the TCP port of the
service, i.e. in a web server to Port 80.
The SYN Rate Limiter function reduces the number of SYN packets,
sent to the local network. This is disabled by default (status light
shows red).
Click the Enable button to enable the function (status light shows
green).
System Information
Packet Filter Live Log: The
Packet
Filter
Live
Log
monitors the packet filter
and NAT rules in place on the
Security system. The window
provides a real-time display of packets intercepted by the packet
filter. This is especially useful in troubleshooting and debugging
packet filter rules. If, after the security system starts, a networked
application, such as online banking, is not accessible, the Packet Filter
Live Log can help you reconstruct which packets are being blocked by
the packet filter.
The Current Packet Filter
rules
and
Current
NAT
rules editing fields show all
current rules in place in the
firewall kernel.
By clicking Show button, a
new window will appear. This
window
shows
a
real-time
display of packets that have
205
Using the Security System
been dropped by the security system.
Click the stop Live Log/start Live Log button to pause or unpause
the real-time display.
Note:
Please note that only those processed rules will be filed in a protocol,
for which the Log function has been enabled under Packet
Filter/Rules!
Current System Packet Filter Rules: The Current Packet Filter
rules window provides detailed information for expert administrators.
The table shows all rules in real time, including system generated
ones, and is taken directly from the operating system kernel.
Current System NAT Rules: As with the current filter rules,
Current NAT rules displays all user- and system-defined NAT rules.
Connection Tracking Table: This menu shows a list of all current
connections and the connection parameters.
206
Using the Security System
5.6. Application Gateways (Proxies)
While a Packet Filter filters packets at the network level, Proxies
(also called Application Gateways)
offer control and security at
the application level by preventing a direct connection between client
and server.
Each Proxy can also provide further security services for its service.
Since each proxy knows the context of its service, extensive security
and protocol options are being offered. This intensive protocol
analysis is made possible by well-defined and well-supported protocol
standards. The proxies concentrate on the most essential information.
In the Proxies tab, select the Proxies with the same name and
configure the settings. By default, all proxies are disabled. This
security system contains proxies for HTTP (Web), DNS (Name
server), SOCKS (point-to-point connections), POP3, SMTP (e-mail),
and Ident.
207
Using the Security System
5.6.1.
HTTP/Surf Protection
The HTTP menu allows you
to configure the security
system as a HTTP Caching
Proxy. This proxy can provide caching services in addition to simple proxy services, resulting in dramatic
performance increases: because the system can store
a
copy
of
often-visited
pages locally, these pages
do not need to be loaded
across the Internet.
Note:
WebAdmin should not be used through a proxy. Configure your
browser so that connections to the security system’s IP address do
not use a proxy server.
Disabling Netscape Communicator, Proxy:
1.
In
Netscape,
open
the
Edit/Settings/Advanced/Proxies
menu.
2.
Under Manual Proxy Configuration click Show.
3.
In the No Proxy for this address field, enter the IP address of
your security system.
4.
208
Click OK to save your changes.
Using the Security System
Disabling Proxy Use with Microsoft Explorer:
1.
In Explorer, open the Extras/Internet Options menu.
2.
Choose the Connections tab.
3.
Open the LAN Settings/Advanced menu.
4.
Under Exceptions, enter the IP Address of your security system.
5.
Click OK to save your settings.
The HTTP proxy controls web transactions using the HTTP Protocol
(usually TCP/IP Port 80). Please note that some web servers transmit
some data, in particular streaming video and audio, over a port other
than 80. These requests will not be noticed when the proxy is in
Transparent mode: to support such requests, you must either use a
different mode, or enter an explicit rule in the Packet Filter/Rules
allowing them.
Example:
Source: a local network
Service: service with target address (the service must first be
defined in the Definitions/Services menu)
Destination: IP address of the web server (or Any)
Action: Allow
HTTPS (TCP/IP Port 443) data is passed directly through the security
system without processing.
Note:
In order to use the Proxy in Standard mode, the client Browser
must be configured with the TCP/IP Address of the security
system and the proxy port configured in the Proxies/HTTP menu.
In addition, the HTTP proxy service requires a valid Name server
(DNS). Without configuring the client browser, the Proxy can only
be used in Transparent mode.
209
Using the Security System
Global Settings
Operation Modes:
Standard: In this mode, you must select all networks which should
be allowed to use the HTTP proxy service. If a browser on a nonconfigured network is configured to use the proxy, it will have no
access to HTTP services.
If a browser on a non-proxied network is not configured to use the
proxy, an appropriate packet filter rule can allow (un-proxied) access
to HTTP services.
Example:
Source: IP address of a local client
Service: HTTP
Destination: IP address of the web server or Any
Action: Allow
To use the proxy, configure the client browser proxy settings to use
the IP address of the security system and port 8080.
Transparent: In this mode, the system notices HTTP requests on the
internal network, automatically processes them, and forwards them to
the remote server. The client browser is entirely unaware of the proxy
server.
The
administration
advantage
or
of
this
configuration
is
mode
is
required
that
on
no
the
additional
client;
the
disadvantage is that only pure HTTP (port 80) requests can be
forwarded.
All networks allowed to use the transparent proxy must be explicitly
listed in the Allowed Networks menu. When Transparent mode is
used, the client browser settings cannot be used to control proxy
settings. Moreover, no data can be downloaded from a FTP server in
this mode. HTTPS connections (SSL) must be executed via a Packet
Filter.
210
Using the Security System
User Authentication: This mode complies with the functions of the
Standard mode. In addition, user access to the HTTP proxy is only
authorized after previous Authentication.
Note:
Changes in Proxies become effective immediately, without further
notice.
Enabling the HTTP Proxy:
1.
In the Proxies tab, open the HTTP menu.
2.
Enable the proxy by clicking the Enable button in the Global
Settings window.
Another entry window will open.
3.
In the Operation mode drop-down menu, select the mode to
use.
Note again that some modes require client-side configuration.
The modes are described in chapter "Operation Modes“.
Having set the Standard or Transparent mode, continue with
step 5.
4.
If you have selected the User Authentication mode in the
Operation mode drop-down menu, define the method of user
authentication to use here.
Authentication Methods: Only those authentication methods
that you have configured in the Settings/User Authentication
menu are available here.
If you have configured the Local Users method, use the
Allowed users selection menu to choose users allowed to use
the proxy. Local users are defined in the Definitions/ Users
menu.
211
Using the Security System
5.
In the Log level drop-down menu, choose the appropriate level
of logging.
Full: All relevant information is recorded.
Access Log only: The log only records access information, for
example URL accessed and username/IP address of the client.
None: No information about the proxy use is recorded.
6.
The Anonymity drop-down menu allows you to choose how
much information about the client is passed on to the remote
server in HTTP Request Headers.
Standard: The following headers are blocked: Accept-Encoding,
From, Referrer, Server, WWW-Authenticate and Link.
None: Client headers are not changed at all.
Paranoid: All headers except those listed below are blocked.
Additionally, the “User-Agent” field will be changed so that no
information about the internal client is available.
Allow, Authorization, Cache-Control, Content-Encoding, ContentLength, Content-Type, Date, Expires, Host, If-Modified-Since,
Last-Modified,
Location,
Pragma,
Accept,
Accept-Language,
Content-Language, Mime-Version, Retry-After, Title, Connection,
Proxy-Connection and User-Agent.
Note:
In Standard and Paranoid modes, the proxy blocks all cookies.
If you wish to use cookies, you should use the none mode.
7.
Use the Allowed networks selection menu to select which
networks should be allowed to use the proxy.
A description of how to use the selection field tool can be found
in chapter 4.3.2 on page 36.
All settings take effect immediately and will be saved if you leave this
menu. Only the HTTP proxy can be accessed from the allowed
networks.
212
Using the Security System
See also the functions in the Advanced window.
Surf Protection (Content Filter)
The Surf Protection Profiles function allows you to
produce
profiles,
which
prevent access to certain
websites. These profiles can
then
be
associated
with
certain users or networks,
thus allowing control over which sites users may access. The
categories are based on the URL data base from Cobion Security
Technologies and can be edited in the Surf Protection Categories
table.
Each Surf Protection Profile additionally contains a Content Filter
with protection mechanisms.
Those protection mechanisms are:
•
Virus Protection (VP)
•
Embedded Object Filter
•
Script Content Filter
This Surf Protection option can only be configured when the HTTP
proxy is enabled.
213
Using the Security System
Surf Protection Categories
The Surf Protection
option contains 17 defined Surf Protection
Categories. The categories are based on
the
URL
data
base
from Cobion Security
Technologies
and
can be edited in this
table.
Editing Surf Protection Categories:
1.
Enable this option by clicking the Enable button in the Surf
Protection (Content Filter) window.
The status light will show green and an advanced entry window
will open.
2.
Click the Show/Hide button to open the table with the
categories.
The name of category is displayed in the Name field. This name
will be selected later from the Profiles Table. The Subcategories
field lists the subcategories.
3.
Now click on the entry, you wish to edit.
Clicking on Name opens another entry window. If you click on
the subcategories, another selection window will open. All available subcategories will be listed in this selection field.
214
Using the Security System
Save your changes by clicking on the Save button. To keep an
entry, click cancel.
4.
To close the table, click on the Show/Hide button.
The Surf Protection Categories window will close.
The Profiles Table
Each Surf Protection Profile will be displayed in the Profiles table
through a separate line: The different settings will either be displayed
as alphanumeric signs or as symbols. All settings can be edited by
clicking on the correspondent field.
A Surf Protection Profile contains two function groups: The Surf
Protection
Categories
with
the
additional
functions
Blacklist,
Whitelist and Content Removal, and the Content Filter. The Surf
Protection Categories prevent the access to Websites with a specific
content. The Content Filter contains a Virus Protection function and
filters Websites with specific technical components.
215
Using the Security System
The Functions
The following picture shows a Surf Protection profile:
The functions from the left to the right are:
Deleting Profiles (
): Click on the trashcan icon to delete a profile
from the table.
Name: This is the name of the Surf Protection Profile. This Name is
necessary to assign this profile to a specific Network or User.
Open the editing window by clicking on the field with the entry (e.g.
Default). Save your changes by clicking on the Save button. To keep
an entry, click cancel.
URL Whitelist: This is an additional function from the Surf Protection Categories. With this access control list you can "allow" the
access to specific Websites with a content that matches the subjects
in the Surf Protection Categories.
Example: If you have chosen the Information and Communication subject in the Surf Protection Categories menu, but wish to
explicitly allow access to the www.astaro.org website, simply add
this address to the Whitelist.
216
Using the Security System
Open the access control list
by clicking on the field with
the entry (e.g. 0 entries).
Enter the Internet addresses
one beneath the other into
the entry field (e.g. www\
.astaro\.org).
Comments
must be identified with a #
sign at the beginning of each
line. Save your changes by
clicking on the Save button.
To
keep
an
entry,
click
cancel.
URL Blacklist: This is an additional function from the Surf Protection Categories. With this access control list you can "allow" the
access to specific Websites with a content that doesn't match the
subjects in the Surf Protection Categories.
Open the access control list by clicking on the field with the entry
(e.g. 0 entries). Enter the Internet addresses one beneath the other.
Comments must be identified with a # sign at the beginning of each
line.
Save your changes by clicking on the Save button. To keep an entry,
click cancel.
Surf Protection Categories: In this field, choose the kinds of
websites to which access should not be allowed.
Open the access control list by clicking on the field with the entry
(e.g. 0 entries).
The Surf Protection option contains 17 defined Surf Protection
Categories. Those 17 categories are administered and edited in the
same table.
The administration of the Surf Protection Categories is described
on page 214.
217
Using the Security System
Embedded Object Filter: This function deletes embedded objects
such as ActiveX, Flash or Java from the incoming HTTP traffic.
Security Note:
Enable this function only, if high security demands apply to your
network.
Clicking on the symbol enables (
) and disables (
) the Em-
bedded Object Filter.
Script Content Filter: This function deletes script contents, such as
Java and VBScript from incoming HTTP traffic.
Security Note:
Enable this function only, if high security demands apply to your
network.
Clicking on the symbol enables (
) and disables (
) the Script
Content Filter.
Content Removal: This is an additional function of the Surf Protection Categories. This access control list allows you to filter
Websites that contain specific expressions. Such texts, which contain
an expression from the access control list, will be replaced by a HTML
comment.
Open the access control list by clicking on the field with the entry
(e.g. 0 entries). Enter the expressions one beneath the other.
Comments must be identified with a # sign at the beginning of each
line.
Save your changes by clicking on the Save button. To keep an entry,
click cancel.
Virus Protection: This functions checks incoming traffic for dangerous content such as viruses.
Clicking on the symbol enables (
Protection.
218
) and disables (
) the Virus
Using the Security System
Enabling Surf Protection, adding Profiles:
1.
Enable this option by clicking the Enable button in the Surf
Protection (Content Filter) window.
The status light will show green and an advanced entry window
will open.
By Default the Profiles table contains a Blank Surf Protection
Profile.
2.
To add a new Blank Surf Protection Profile to the table, click
on the Add blank Profile button.
There you can edit the Surf Protection Profile.
Editing Surf Protection Profiles:
1.
In the Profiles table go to the Surf Protection Profile that you
wish to edit.
2.
In the Name field enter a descriptive name for the Surf
Protection Profile.
3.
Now make the settings for the Surf Protection Categories
functional group in the following order.
Surf Protection Categories: In this field, choose the websites
topics to which access should be blocked from your network.
URL Whitelist: In the access control list enter those Internet
addresses, for which you wish to "allow" access, even though
their topic matches a topic in the Surf Protection Categories
field.
URL Blacklist: In the access control list enter those Internet addresses, for which you wish to "forbid" access, even though their
topic doesn't match a topic in the Surf Protection Categories
field.
219
Using the Security System
Security Note:
In the HTTP protocol the header of the HTTP Cache Proxy
Squid will be filtered.
This is different in the HTTPS protocol - in this case, the
header will only pass through. This means that the Surf
Protection module cannot block URLs on the basis of
White- or Blacklists for HTTPS connections.
Content Removal: In the access control list enter those
expressions that should be deleted from the Website.
4.
Make the settings for the Content Filter functional group.
Embedded Object Filter: Clicking on the symbol enables (
and disables (
)
) the filter.
Security Note:
Enable the Embedded Object Filter function only, if high
security demands apply to your network.
Script Content Filter: Clicking on the symbol enables (
disables (
) and
) the function.
Security Note:
Enable the Embedded Object Filter function only, if high
security demands apply to your network.
Virus Protection: Clicking on the symbol enables (
disables (
) and
) the function.
The Surf Protection Profile is now edited. Now assign the profile in
the Profile Assignment table to a Network or to a Local User.
220
Using the Security System
The Profile Assignment Table
The Surf Protection Profiles from the Profiles table are assigned to
Local Users or Networks in the Profile Assignment table.
To assign a Surf Protection Profile to a local user, the HTTP proxy
must be used in the User Authentication Mode. The assignment of
Profiles to a network is possible in every operation mode.
Important Note:
If you are simultaneously assigning a Profile to a local user and to
a network, this Profile will only take effect, if the user accesses the
HTTP proxy from the "configured“ network! Only one Surf Protection Profile can be configured for each user or network.
If you have configured the User Authentication configuration mode
in the Global Settings window, the Profile Assignment via dropdown menu will be displayed above the Profile Assignment table. By
default this is set to Local Users + Network blocks.
If you have configured a radius or LDAP-Server in the System/User
Authentication menu, they will be displayed in the drop-down menu.
Once you have selected one of the servers, the Profile Assignment
table will be masked.
221
Using the Security System
The Functions
The following picture shows a Profile assignment:
The functions from the left to the right are:
Deleting Profile assignments (
): Click the trashcan icon to delete
an assignment from the table.
Position number: The workout sequence will be displayed in the
table through the respective Position number.
Clicking on the field with the entry will open the drop-down menu.
This drop-down menu allows you, to change the order of the profile
assignments. Save your changes by clicking on the Save button. To
keep an entry, click cancel.
Status light: The status light refers to the status of the profile
assignment: Each new assignment is not yet enabled (status light is
red).
The profile assignment will be enabled by clicking on the status light
(status light is green).
Profile Name: Select the Surf Protection Profile in this field from
the Profiles Table.
Clicking on the field with the entry opens the drop-down menu. Save
your changes by clicking on the Save button. To keep an entry, click
cancel.
Assigned local Users: Select the local user from this field.
Clicking on this field with the entry opens the selection field. Save
your changes by clicking on the Save button. To keep an entry, click
cancel.
222
Using the Security System
Important Note:
If you are simultaneously assigning a Profile to a local user and to
a network, this Profile will only take effect, if the user accesses the
HTTP
proxy
from
the
"configured“
network!
Only
one
Surf
Protection Profile can be configured for each user or network.
Assigned Network Blocks: Select the Network from this field.
Clicking on this field with the entry opens the selection field. Save
your changes by clicking on the Save button. To keep an entry, click
cancel.
Assigning Surf Protection Profiles:
By default, the table contains already a Blank Assignment. If this
blank assignment has not been edited yet, continue with step 1.
1.
By clicking on the Add blank Assignment button, add a new
blank assignment.
2.
From the Profile Name field, select the Surf Protection
Profile.
3.
From the Assigned local Users field, select the local user for
this profile.
4.
From the Assigned Network Blocks, select the network for this
profile.
5.
Enable the profile assignment by clicking the status light.
The status light is green.
If a user or computer defined in the profile attempts to access a
blocked website, access will be blocked, and the user will receive a
message explaining why.
223
Using the Security System
Advanced
Caching: This function buffers often-used Websites to
the
HTTP
Proxy
Cache.
This is enabled by default
(status light shows green).
Clicking
on
the
Disable
button disbles this function.
Block CONNECT Method: All HTTP-connection requests will be
blocked by the HTTP-proxy. Only the HTTP-methods GET and PUT
will be allowed through the proxy.
Each Client Request will be introduced through the information of the
method. Methods define the respective action for requests. The
current HTTP-specification offers eight methods: OPTIONS, GET,
HEAD, POST, PUT, DELETE, TRACE and CONNECT. Only the GET and
PUT methods are explained in this section.
The GET method is used with requests from a document or another
source. A source in this case is defined through the request-URL.
There are two types: Conditional GET and partial GET. With the
conditional-GET-type
the
request
of
data
depends
on
certain
conditions. The detail of these conditions is stored in the header-field
Conditional. Often used conditions are for example If-Modified-Since,
If-Unmodified-Since or If-Match. This condition helps to considerably
reduce network utilization, since only the necessary data are
forwarded. In practice, proxy servers, for example, use this function
to prevent that data that are already stored in cache are forwarded
several times. Also the partial GET-method has the same purpose. It
uses the range-header-field that only forwards parts of the data,
which, however, cannot be processed by the client yet. This technique
is used for the resumption of an interrupted data transfer.
The PUT method allows for a modification of existing sources and/or
for the creation of new data on the server. In contrast to the POST224
Using the Security System
method, the URL in the PUT-request identifies the data sent with the
request and not the source.
Clicking on the Enable button enables the function (status light is
green).
Allowed Target Services: Use the Allowed target services
selection menu to choose services that the HTTP proxy should be
allowed to access. By default, the services with the ports are already
available, to which a connection is considered as being safe.
TCP Port: Enter the TCP/IP-Port in the entry field. By default, this
is set to the TCP/IP-Port 8080.
Clear HTTP Proxy Cache: The HTTP Proxy Cache proxy stores a
copy of often-visited pages locally, reducing load times.
By clicking the Start button, the cache will be cleared, and any new
accesses will be loaded from the remote Internet site.
5.6.2.
DNS
The DNS Proxy service allows you to provide internal
clients with a secure and
efficient name server service. If you select multiple
remote name servers, they
will be queried in the order
they are entered.
If no name servers are entered in the Forwarding Name Servers
menu, the proxy will use the Internet-wide ROOT name servers. If
you or your ISP runs a name server that is closer, you should enter
its IP address here. This means, however, that they are usually slower
than closer name servers.
The ROOT name servers are an integral part of the Internet. 15 ROOT
225
Using the Security System
name servers are distributed worldwide and are the basic instance for
all secondary name servers.
Tip:
Even if you do not plan to use the DNS proxy, you should enter the
address of your provider’s DNS server address as a forwarding
server. Those will be used by the firewall itself, even if the proxy is
disabled. This contributes to the discharge of the root name server
and the firewall produces only local queries, which generally receive
faster replies.
Configuring the DNS Proxy:
1.
In the Proxies tab, open the DNS menu.
2.
Click the Enable button to start the proxy.
Another entry window will open.
3.
Make the following settings:
A description of how to use the selection field tool can be found
in chapter 4.3.2 on page 36.
Interfaces to listen on: Select which network cards the DNS
proxy server should be reachable on. This should usually only be
the internal network cards.
Network cards are configured in the Network/Interfaces
menu. Further information is available in chapter 5.3.2 on page
119.
Allowed Networks: Select which networks should have access
to the proxy server.
Security Note:
In the Allowed networks menu, do not select Any unless
absolutely necessary. If any is selected, the DNS Proxy
can be used by any Internet user.
226
Using the Security System
Forwarding Name Servers: Enter the IP addresses of your
name server here.
Click Add to add each name server to the list.
Ordered Lists are described in chapter 4.3.4 on page 39.
All settings take effect immediately and will be saved if you leave this
menu.
5.6.3.
SOCKS
SOCKS is a generic proxy,
used by many client applications. Examples include Instant Messaging Clients such
as ICQ or AIM, FTP clients,
and RealAudio. SOCKS can
build
TCP
connections
for
client applications, and can
also provide incoming (listening) TCP and UDP ports. This is especially
important for systems using NAT, as SOCKS mitigates the drawbacks
of having all internal clients use the same external address. This
security system supports the protocols SOCKSv4 and SOCKSv5.
Please note, however, that the SOCKSv4 protocol does not support
User Authentication.
Note:
If you wish to use SOCKSv5 with name resolution, you must also
activate the DNS proxy service.
227
Using the Security System
Configuring the SOCKS Proxy:
1.
In the Proxies tab, open the SOCKS menu.
2.
Click the Enable button next to Status to start the proxy.
Another entry window will open.
3.
Make the following settings:
A description of how to use the selection field tool can be found
in chapter 4.3.2 on page 36.
Allowed Networks: Here you can select the networks and
hosts that should be allowed to use the proxy.
All settings take effect immediately and will be saved if you leave this
menu.
SOCKS-Proxy with User Authentication:
If you have enabled the User Authentication function, proxy users
must use a username and password to log into the SOCKS proxy.
Because only SOCKSv5 supports User Authentication, SOCKSv4 is
automatically disabled.
The Authentication Methods selection menu allows you to select
the user authentication method to be used. Only those authentication
methods, you have configured in the Settings/User Authentication
menu are available here. If you choose to use the Local Users
method, you can select which local users may access the SOCKS
Proxy.
Local Users are managed in the Definitions/Users menu.
228
Using the Security System
5.6.4.
POP3
POP3
stands
for
Post
Office Protocol 3: This is a
protocol, which allows the
retrieval of e-mails from a
mail
server.
logical
POP3
is
the
opposite of SMTP.
SMTP stands for Simple Mail
Transfer Protocol. This protocol is used to deliver e-mails
to a mail server.
This menu allows you to configure the POP3 Proxy for incoming emails. The POP3 proxy works transparently, requiring no configuration
on the client side. POP3 requests coming from the internal network on
port 110 are intercepted and redirected through the proxy. This
process is not visible to the client. The advantage of this mode is that
no additional administration or configuration is required on the client
of the end user.
Configuring the POP3 Proxy:
Normally, the POP3 proxy must only be enabled in order to process
POP3 requests, as it proxies for all networks by default. The
Configured Proxied Networks displays which networks are to be
allowed.
If only POP3 requests from certain networks should be forwarded, the
configuration must be changed. Note that the drop-down menus
contain only those networks you have already defined in the
Definitions/ Networks menu.
Example: POP3 queries from the subnet 192.168.0.0/ 255.255.0.0
to pop.yoursite.com should be forwarded through the proxy. These
networks must first be defined in the Networks menu. Once this is
done, continue as follows:
229
Using the Security System
1.
In the Proxies tab, open the POP3 menu.
2.
Click the Enable button next to Status to start the proxy.
An advanced entry window will open.
3.
In the
Proxied Networks window, choose the networks that
the proxy should intercept requests from and to.
Source: Choose the source address here.
Example: The name of the 192.168.0.0/255.255.0.0 network.
Destination: Choose the destination address here.
Example: The name of the pop.yoursite.com network.
4.
Confirm your selection by clicking Add.
Content Filter
Virus Protection: This option scans e-mails and attachments passing through
the
proxy
for
dangerous
contents such as viruses or
Trojan horses. The results of
the scan are inserted into a
header of the message. Any
messages
blocked
by
the
proxy will be shown in the
Proxies/Proxy Content Manager menu. Enable the Virus Protection by clicking on the Enable button (status light is green).
Spam Protection: This option heuristically checks incoming e-mail
for characteristics suggestive of spam. This system uses an internal
database of heuristic tests and characteristics, making the test independent from sender information, and also more reliable.
Two Thresholds can be defined for the Spam Score. This ensures
that potential SPAM e-mails are treated differently by the Firewall.
230
Using the Security System
Default settings:
Thresholds
Pass when Score exceeds: 03 (aggressive)
Quarantine when Score exceeds: 05 (reasonable)
The first threshold implicates that e-mails from level 3 on are filtered,
but allowed through. With the help of the attached Header the e-mail
on the mail-server or in the e-mail-program of the recipient can be
sorted or filtered. For the second threshold the e-mail will be accepted
but put into quarantine.
Basically, the Threshold with the higher level is treated more
severely.
Important Note:
On busy systems, the Spam Protection may require a large percentage of system resources.
Pass/Quarantine when Score exceeds: These drop-down menus
can be used to select the strategy to use in marking messages as
spam. The difference between the maximum values is defined
through the probability that legitimates messages, such as HTML
Newsletters will be blocked. It is possible to set a value between 1
and 15 in the drop-down menu. With level 1, the e-mails are already
treated with a low spam score. The following Levels serve as clue:
•
Aggressive (03): This strategy will catch most spam messages.
It may also identify some legitimate messages, for example HTML
newsletters, as spam.
•
Reasonable (05): This strategy is a compromise between
Aggressive and Reasonable
•
Conservative (08): This strategy will only catch messages that
are highly likely to be spam. Legitimate messages are unlikely to
be caught.
231
Using the Security System
The following actions are preset:
•
Quarantine: The e-mail will be accepted, but kept in quarantine.
The Proxy Content Manager menu will list this e-mail with status
Quarantine. This menu presents further options, including options
to read or to send the message.
•
Pass: The proxy will add a Header to the message noting that it
has found a potentially dangerous string, but will then allow the
message to pass. A Header will be added to the e-mail, by which
it can be sorted or filtered on the mail server or in the e-mail
program of the recipient. In addition, the word SPAM will be
added to the message subject line.
Die Header:
Many of the SMTP proxy functions will add headers to the messages
scanned. The Header will inform the user on specific characteristics of
a message. If you select the Pass action, recipients can configure
their e-mail programs to filter messages with high spam scores.
The following list contains all possible Headers:
•
X-Spam-Score: This header is added by the Spam Detection
module. It contains a score, consisting of a numerical value and of
a number of minus and plus characters. The higher the value, the
more likely it is that the message is spam.
If you select the Pass action under Spam Protection, recipients
can configure their e-mail programs to filter messages with high
spam scores.
•
X-Spam-Flag: This header is set to Yes when the proxy classifies
a message as spam.
•
X-Spam-Report: The proxy identified a
message as spam. The
added Multiline Header contains a readable and accessible antispam report.
232
Using the Security System
•
X-Infected: This header is added if a virus is detected within the
message. The value of the header is the name of the virus found.
•
X-Contains-File: When the File Extension Filter is enabled and
an attachment with a potentially dangerous extension is found, the
proxy will add this header.
•
X-Regex-Match: When the Expression Filter is enabled and an
e-mail contains a string from the control list.
Spam sender whitelist: This control list can only be defined for the
Spam Protection option. Enter the e-mail addresses of those senders into the list, whose messages you wish to block.
File Extension Filter: The firewall filters attachments with the extensions from the control list.
Expressions Filter: Various viruses can be identified because of
known strings – such as the IloveYou virus. The strings are entered
into the control list. If an e-mail contains this string, it will be blocked.
233
Using the Security System
5.6.5.
Ident
The Ident protocol allows
external servers to associate
a
username
with
given TCP connections.
While this connection is not encrypted, it is nevertheless necessary for
many services.
If you enable the Ident function, the security system supports Ident
queries. The system will always reply with the string that you define
as Default Response, irrespective from which local service the
connection will be started.
Forward Connections: Ident queries cannot be answered through
Connection Tracking. You can get around this difficulty if you use
the Masquerading function: in that case, the Forward Connection
function will pass the ident request on to the internal masquerading
host.
Please note, however, that the actual (internal) IP address will not be
released. Instead, the system will query the internal machine, and
simply pass the response string to the remote server. This is often
useful for internal clients with a mini-ident server, such as the ones
often included in IRC and FTP clients.
234
Using the Security System
5.6.6.
SMTP
An SMTP Proxy allows you
to protect an internal mail
server from remote attacks.
While forwarding and receiving messages, the proxy can
also scan them for potentially
dangerous
contents.
This
menu also allows you to configure anti-spam parameters
in order to block unwanted emails.
This
menu
allows
you
to
configure the POP3 Proxy
for
incoming
e-mails.
The
SMTP Proxy receives all e-mails at the gateway and then forwards
them to their destination. Because there is no direct contact between
internal and external machines, only data is transferred, and no
protocol errors will propagate. The SMTP proxy monitors the SMTP
protocol on TCP port 25.
Note:
In order to use the SMTP Proxy correctly, a valid name server
(DNS) must be activated. System notifications are sent to the
administrator even if the SMTP proxy is disabled.
235
Using the Security System
Configuring the SMTP Proxy:
1.
In the Proxies tab, open the SMTP menu.
2.
Click the Enable button next to Status to start the proxy.
3.
In the Global Settings window, configure the basic settings.
Hostname (MX): Enter the hostname here.
Important Note:
If you wish to use TLS encryption, this hostname must be
identical with the one listed in your DNS server’s MX record.
Otherwise, other mail servers using TLS will refuse to send
incoming mails.
Postmaster Address: Enter the e-Mail address of the postmaster here.
Max message size: Enter the maximum message size for inand out-bound mail messages. Normal values are 20 or 40 MB.
Please note that the encoding used to transmit e-mails can make
the size of the message larger than the files sent.
4.
Save your settings by clicking Save.
5.
Enable the DoS Protection by clicking the Enable button.
In order to protect the security system against a Denial of
Service (DoS) attack, a maximum of 25 incoming concurrent
connections are supported. The 26th connection will not be
accepted.
By default, the DoS Protection function is enabled.
6.
In the Incoming Mail window, set the route for incoming mails.
Domain Name: In order to send mails for a certain domain to
the correct machine, the domain name (e.g., mydomain.com)
must be configured here.
SMTP Host: All e-mails for this domain can be forwarded to a
certain host. This will normally be a host like Microsoft
236
Using the Security System
Exchange Server or Lotus Notes. The host must be defined in
the Definitions/Networks before it will appear in the dropdown menu.
You can also set the system to forward e-mails to the system
specified by the MX record. You should take care that the firewall
itself is not the MX host for the domain.
7.
Confirm your selection by clicking Add.
Recipient Verification: The SMTP proxy will only accept incoming e-mails after verifying that the receiving address exists.
This will dramatically reduce the number of spam messages received, as only messages with valid destination addresses will be
accepted.
This function requires that the internal SMTP server reject
messages to unknown addresses. The basic rule: The basic rule
is that if the mail server rejects a message, then so too will the
firewall.
8.
In the Outgoing Mail window, select the Allowed Networks or
hosts to which outgoing mail should be proxied.
Security Note:
Messages sent from those networks will never be scanned
by Spam Detection.
Use Smarthost: If you wish to use an Upstream Smarthost to
deliver messages, enable this function and enter the IP address
of the smarthost here. In this case, the proxy will not attempt to
deliver messages itself, but will instead forward them to the
smarthost. The proxy will, however, deliver messages locally to
domains defined in the Incoming Mail window.
237
Using the Security System
Encryption/Authentication
The TLS Transaction Encryption function allows you to automatically encrypt in- and out-going e-mails at the transport layer. You
must first confirm that the remote host supports this function. TLS is
used for encryption, not just authentication. SMTP is generally not
encrypted and can easily be read by third persons. The function
should therefore be enabled.
Important Note:
Some mail servers, such as Lotus Domino, use non-standard
implementations of TLS. While these servers claim to support TLS
during connection negotiation, they cannot establish a TLS full
session. If TLS is enabled, it will not be possible to send messages to
these servers. In such situations, please contact the administrator of
the mail server.
If the TLS Transaction Encryption function is activated, you can
also use SMTP Authentication. This allows mail clients such as
Microsoft Outlook, Outlook Express, or Netscape Messenger to
authenticate themselves to the SMTP Proxy. This is especially useful
for clients with dynamic IP addresses, where the client IP address
cannot be specified in the Outgoing Mail menu.
When configuring clients, please note that SPA (Secure Password
Authentication) should not be used. SPA is an alternative encryption
method, which is not supported by this security system. You should
use an unencrypted authentication method instead, and use TLS (or
SSL) to encrypt the session.
The Authentication Methods selection field allows you to select the
user authentication method to be used. Only those authentication
methods you have configured in the Settings/User Authentication
menu are available here.
Local users are defined in the Definitions/Users menu.
238
Using the Security System
Global Whitelist
Trusted Hosts/Networks:
In
the
hierarchy
list
a
Global Whitelist can be
defined with reliable hosts
or networks, which in this
case are excluded from the following options:
•
Realtime Blackhole Lists
•
Sender Verification
•
MIME Error Checking
•
Spam Detection
•
Expression Filter
This implicates, that the necessary computing power for scans is
reduced and that problematic hosts can be excluded from Content
Scanning.
Trusted Domains: In the ordered list a Global Whitelist can be
defined with a reliable Domain name.
Security Note:
This function should only be used carefully, since sender addresses can easily be falsified.
239
Using the Security System
5.6.6.1.
Virus Protection/Content Filter
Block RCPT Hacks
When this function is enabled, the proxy will reject e-mails with a
sender address containing the characters !, %, /, or |. In addition,
addresses with an extra @ symbol, or which begin with a dot (.) will
also be blocked.
Sender Blacklist
This function allows you to create a list of sender addresses, for
example those of known spam senders. The proxy will then reject all
messages with these addresses in either the From or Reply-To
headers.
Enter the e-mail addresses according to the following description into
the Patterns control list:
•
To block e-mails from a certain address.
Entry: user@domain.com
•
To block all e-mails from a certain domain.
Example: *@domain.com
•
To block all e-mails from a certain user, no matter what domain is
used to send the message.
Example: user@*
The function of the Control List is identical to the Ordered List and
described in chapter 4.3.4 on page 39.
If the firewall receives an e-mail from a blocked address, a 5xx error
code will be issued with the message Your address (envelope or
header) is blacklisted at this site.
240
Using the Security System
MIME Error Checking
The MIME Error Checking module can detect errors in messages
that have been encrypted with MIME. MIME stands for Multipurpose
Internet Mail Extensions. MIME defines the structure and the
composition of e-mails and of other Internet messages. This is an
encoding
rule,
which
allows
for
the
transmission
of
non-text
documents, e.g. pictures, audio and video in text based transmission
systems. The non-text elements are encrypted at the sender and
decrypted at the receiver.
The MIME Error Checking module can help detecting attacks, in
which error tolerance variations in the MIME-decryption-software are
being utilized.
Action: This drop-down menu allows you to select the action the
proxy should take upon finding a message with a filtered string. The
following actions are possible:
•
Reject: The message will be bounced back to the sender with a
5xx error message. The bounce message sent to the sender will
also contain an explanation of why the message was blocked.
•
Blackhole: The e-mail will be accepted and silently dropped. Do
not use this action unless you are absolutely certain no legitimate
e-mails will be lost.
•
Quarantine: The e-mail will be accepted, but kept in quarantine.
The Proxy Content Manager menu will list this e-mail with status
Quarantine. This menu presents further options, including options
to read or to send the message.
•
Pass: The e-mail will be treated by the filter, but allowed to pass.
A Header will be added to the e-mail, by which it can be sorted or
filtered on the mail server or in the e-Mail programs of the
recipient.
241
Using the Security System
Trigger on: In this drop-down menu you define, which errors cause,
that the e-mail is treated according to the Action function:
•
Level 1: This step causes, that only e-mails with most serious
errors are treated. This setting is recommended, since many users
use a deficient encryption program, that already responds in the
higher levels (Level 2 und 3).
•
Level 2: With the exception of the e-mails with the ordinary
errors, all are being treated.
•
Level 3: Any e-mails with errors are being treated.
File Extension Filter
This module allows the firewall to selectively filter attachments based
on their file extensions. The extensions to filter can be selected in the
Extensions list tool.
Action: This drop-down menu allows you to select the action the
proxy should take upon finding a message with a filtered string. The
following actions are possible:
•
Reject: The message will be bounced back to the sender with a
5xx error message. The bounce message sent to the sender will
also contain an explanation of why the message was blocked.
•
Blackhole: The e-mail will be accepted and silently dropped. Do
not use this action unless you are absolutely certain no legitimate
e-mails will be lost.
•
Quarantine: The e-mail will be accepted, but kept in quarantine.
The Proxy Content Manager menu will list this e-mail with status
Quarantine. This menu presents further options, including options
to read or to send the message.
•
Pass: The e-mail will be treated by the filter, but allowed to pass.
A Header will be added to the e-mail, by which it can be sorted or
filtered on the mail server or in the e-Mail programs of the
recipient.
242
Using the Security System
Extensions: Enter the file extensions, such as exe, that the firewall
should filter.
The function of the Control List is identical to the Ordered List and
described in chapter 4.3.4 on page 39.
Virus Protection
The Virus Protection function allows you to check e-mails and
attachments for dangerous contents such as viruses, Trojan horses,
and so on. The results of the scan are inserted into a header of the
message.
If the Virus Protection discovers an infected e-Mail, the message
will be filtered by the firewall. The further handling will be according
to the setting configured in the Action drop-down menu.
Action: This drop-down menu allows you to select the action the
proxy should take upon finding a message with a filtered string. The
following actions are possible:
•
Reject: The message will be bounced back to the sender with a
5xx error message. The bounce message sent to the sender will
also contain an explanation of why the message was blocked.
•
Blackhole: The e-mail will be accepted and silently dropped.
•
Quarantine: The e-mail will be accepted, but kept in quarantine.
The Proxy Content Manager menu will list this e-mail with status
Quarantine. This menu presents further options, including options
to safely read the message.
•
Pass: The e-mail will be treated by the filter, but allowed to pass.
A Header will be added to the e-mail, by which it can be sorted or
filtered on the mail server or in the e-Mail programs of the
recipient.
243
Using the Security System
Expression Filter
There is the chance that new viruses will appear which are not yet
recognized by the firewall. Various viruses can be identified because
of known strings – such as the IloveYou virus. The strings are entered
into this module. If an e-mail contains this string, it will be blocked.
Action: This drop-down menu allows you to select the action the
proxy should take upon finding a message with a filtered string. The
following actions are possible:
•
Reject: The message will be bounced back to the sender with a
5xx error message. The bounce message sent to the sender will
also contain an explanation of why the message was blocked.
•
Blackhole: The e-mail will be accepted and silently dropped.
•
Quarantine: The e-mail will be accepted, but kept in quarantine.
The Proxy Content Manager menu will list this e-mail with status
Quarantine. This menu presents further options, including options
to read or to send the message.
•
Pass: The e-mail will be treated by the filter, but allowed to pass.
A Header will be added to the e-mail, by which it can be sorted or
filtered on the mail server or in the e-Mail programs of the
recipient.
Expressions: Enter the strings to filter in this list.
The function of the Control List is identical to the Ordered List and
described in chapter 4.3.4 on page 39.
244
Using the Security System
Creating rules in Microsoft Outlook 2000:
MS Outlook allows you to sort those e-mails, which had been filtered
and subsequently been allowed to pass through the Firewall, provided
that the Pass function in the Action drop down menu of the
corresponding modules on the Firewall has been selected.
1.
Start MS Outlook.
2.
Click on Inbox.
3.
Open the menu Tools/Rules Wizard.
4.
Click on the button New.
The Rules Wizard opens, in order to set new rules. The Rules
wizard now leads you step-by-step through the configuration.
5.
Which type of rule do you want to create? (step 1)
Select the rule Check messages when they arrive.
Then click on the button Next.
6.
Which condition(s) do you want to check? (step 2)
In this window, select the condition with specific words in the
message header.
In the window Rule description click on the underlined portion
of text and type the header's name into the input field Search
text.
Example: X-Spam-Score
Then click on the button Next.
7.
What do you want to do with message? (step 3)
Define in this window, what has to be done with the filtered email. If for instance, you want to move the filtered e-mails to a
specific folder, select the action move it to a specified folder.
With one click on Specified folder in the window Rule
description, a new menu appears. Here you can either choose
an existing folder or create a new destination folder for the
245
Using the Security System
filtered e-mails. Example: Spam
Click OK to save the new settings in this menu.
Then click on the button Next.
8.
Add exceptions (step 4)
The module Spam Detection heuristically checks incoming emails for certain characteristics. It therefore might be, that safe
messages, e.g. HTML-Newsletter are filtered. This menu allows
you to define exceptions and to thus exclude e-mails, e.g.
messages of a particular sender from this rule.
Then click on the button Next.
9.
Enter a name for this rule (step 5)
Type a distinct name for this rule into the input field. In the
options fields below, you can activate these rules and also apply
them on e-mails, which are already in the Inbox folder. You can
change your settings in the window Rule description.
Then click on the button Finish.
10. Apply rules in the following order (step 6)
In the Rules Wizard you can activate or deactivate the rules by
one click on the option field or execute changes.
In order to close the Rules Wizard, click on the button OK.
246
Using the Security System
5.6.6.2.
Spam Protection
Sender Address Verification
When this function is enabled, the sending address of incoming emails will be checked. And also sending domain will be checked. If the
sending domain does not exist, the e-mail will be rejected.
If the Callout function is also enabled, the proxy will connect to the
mail server of the sending domain and check the sender address
using an RCPT command. If the sending address does not exist, the
proxy will reject messages from it.
Realtime Blackhole Lists (RBL)
The RBL module uses an external database of known spam senders
to check sending addresses. Several services of this type are available
on the Internet. This function helps to massively reduce the number
of spam.
One
commercial
service,
for
example,
can
be
found
at
http://www.mail-abuse.org.
Action: This drop-down menu allows you to define how filtered emails originating from known spam-sending domains should be
handled. The following actions are possible:
•
Warn: If an e-mail is received from an RBL-listed domain, the XRBL-Warning header will be inserted in the message, and the
message will be allowed to pass through the proxy. More
information on inserted headers can be found in the Spam
Detection section.
•
Reject: E-mails from listed domains will not be accepted, and will
instead be bounced back to the sender.
Zone: Enter the addresses of databases to use in this list.
The function of the Control List is identical to the Ordered List and
described in chapter 4.3.4 on page 39.
247
Using the Security System
Spam Protection
This option heuristically checks incoming e-mail for characteristics
suggestive of spam. This system uses an internal database of
heuristic tests and characteristics. making the test independent from
sender information, and also more reliable.
Two Thresholds can be defined for the Spam Score. This ensures
that potential SPAM e-mails are treated differently by the Firewall.
The two Thresholds are equal. Whereas the threshold with the
higher level should be treated more severely. The functioning is
explained below with the help of the default settings.
Default settings:
Threshold One
When Spam Level exceeds: 03 (aggressive),
do this: Pass.
Threshold Two
When Spam Level exceeds: 05 (reasonable),
do this: Quarantine.
The first threshold implicates that e-mails from level 3 on are filtered,
but allowed through. With the help of the attached Header the e-mail
on the mail-server or in the e-mail-program of the recipient can be
sorted or filtered.
For the second threshold the e-mail will be accepted but put into
quarantine.
Basically, the Threshold with the higher level is treated more
severely (do this).
Important Note:
On busy systems, the Spam Detection may require a large
percentage of system resources.
248
Using the Security System
When Spam Level exceeds: This drop-down menu can be used to
select the strategy to use in marking messages as spam. The
difference between the maximum values is defined through the
probability that legitimates messages, such as HTML Newsletters will
be blocked. It is possible to set a value between 1 and 15 in the dropdown menu. With level 1, the e-mails are already treated with a low
spam score. The following Levels serve as clue:
•
Aggressive (03): This strategy will catch most spam messages.
It may also identify some legitimate messages, for example HTML
newsletters, as spam.
•
Reasonable (05): This strategy is a compromise between
Aggressive and Reasonable
•
Conservative (08): This strategy will only catch messages that
are highly likely to be spam. Legitimate messages are unlikely to
be caught.
do this: This drop-down menu allows you to select the action the
proxy should take upon finding a message with a filtered string. The
following actions are possible:
•
Reject: The message will be bounced back to the sender with a
5xx error message. The bounce message sent to the sender will
also contain an explanation of why the message was blocked.
•
Blackhole: The e-mail will be accepted and silently dropped. Do
not use this action unless you are absolutely certain no legitimate
e-mails will be lost.
•
Quarantine: The e-mail will be accepted, but kept in quarantine.
The Proxy Content Manager menu will list this e-mail with status
Quarantine. This menu presents further options, including options
to read or to send the message.
•
Pass: The e-mail will be treated by the filter, but allowed to pass.
A Header will be added to the e-mail, by which it can be sorted or
filtered on the mail server or in the e-Mail programs of the
249
Using the Security System
recipient. In addition, the word SPAM will be added to the
message subject line.
Spam sender whitelist: This control list is defined for the Spam
Protection function. Enter the e-mail addresses of those senders into
the list, whose messages you wish to allow through.
The function of the Control List is identical to the Ordered List and
described in chapter 4.3.4 on page 39.
The Header:
Many of the functions will add headers to the messages scanned:
The Header will inform the user on specific characteristics of a
message. If you select the Pass action, recipients can configure their
e-mail programs to filter messages with high spam scores. The
following is a list of the headers the SMTP proxy may insert:
•
X-Spam-Score:
This
header
will
be
added
to
the
Spam
Detection module. It contains a score, consisting of a numerical
value and of a number of minus and plus characters. The higher
the value, the more likely it is that the message is spam.
If you select the Pass action under Spam Detection, recipients
can configure their e-mail programs to filter messages with high
spam scores.
•
X-Spam-Flag: This header is set to Yes when the proxy classifies
a message as spam.
•
X-Spam-Report: The proxy identified a
message as spam. The
added Multiline Header contains a readable and accessible antispam report.
•
X-Infected: This header is added if a virus is detected within the
message. The value of the header is the name of the virus found.
•
X-Contains-File: When the File Extension Filter is enabled and
an attachment with a potentially dangerous extension is found, the
proxy will add this header.
250
Using the Security System
•
X-Regex-Match: When the Expression Filter is enabled and an
attachment matching the configured regular expression is found,
the proxy will add this header.
•
X-RBL-Warning: When the Realtime Blackhole Lists (RBL)
function is enabled and the sending domain is listed in the Zones
list, this header will be added. Note that this header will only be
added if the RBL system is configured to Warn.
5.6.7.
Proxy Content Manager
The Proxy Content Manager menu allows you to manage all of the
e-mails quarantined by the proxy, as well as those which, because of
an error, the system was unable to forward.
This menu uses the following concepts to display and manage the emails:
251
Using the Security System
ID: Every e-mail in this security system contains a unique ID. This
ID is contained in the header of the message, and is used by the
system to identify messages in the log files. The ID will be displayed,
when you touch the entry in the Type field with the mouse.
Type: Proxy Content Manager distinguishes between the POP3 and
SMTP types of filtered e-mail: If you touch the entry with the mouse,
the Mail-ID will be displayed. Clicking on the entry opens a window
with the content of the message. Thus you can safely read important
messages. Messages of a length of up to 500 lines will be displayed
completely.
Age: This column displays the age of an e-mail, i.e., the period of
time since when the e-mail has arrived to the Internet security
system.
Status: The states of the e-mails are displayed in the Proxy Content
Manager through symbols.
•
deferred (
): The e-mail will be sent to the intended recipient.
Normally, messages of this type are forwarded soon after the
proxy receives them. If, however, temporary problems delivering
the message are encountered, it may remain in the queue with
this status for a short while. Such messages will be delivered as
soon as the destination host can be contacted.
•
Quarantined (
): The e-mail will be quarantined due to the
Quarantine configuration to one of the Content-Filter-Modules.
Unwanted or dangerous content such as a virus have been
discovered in the message. Such messages will remain in the table
until an administrator deletes or sends them.
On the right side, next to the status symbol for those e-mails,
which are kept in quarantine, it is displayed which function blocked
the message:
SP: Spam Protection
VP: Virus Protection
252
Using the Security System
Filter: File Extention Filter
EXP: Expression Filter
MIME: MIME Error Checking
•
permanent error/andauernder Fehler (
): The e-mail con-
tains a permanent error.
Sender: The sender of an e-mail is displayed in this column. For the
SMTP type, this is the sender address on the enveloppe.
For the POP3 type, this is the address of the „From:“-header of an email. If no sender address is displayed, the e-mail contains the
additional status Bounce.
Recipient(s): The recipient of an e-mail is displayed in this column.
For the SMTP type, this is the recipient’s address on the enveloppe.
For e-mails with the deferred status, the delivery status will be
displayed separately for each recipient: Deferred (
error (
) or permanent
).
The drop-down menu at the bottom of the table shows further
functions to manage single e-mails. Click the selection box next to an
e-mail to manage it.
The following functions are available:
Delete: All chosen e-mails will be deleted.
Force delivery: All chosen e-mails will be forwarded to the recipient
addresses, even those having a quarantined status. For e-mails with
a deferred or permanent error status, it is being tried again to
deliver the message. If the system encounters another problem
delivering it, the message will return to its previous status.
Download as .zip file: The chosen e-mails are packed into a zip-file
and then saved to the selected local host.
253
Using the Security System
Global Actions
In order to save disk space on the security system, you can use this
option to delete all messages of a certain type. E-mails being sent or
forwarded while the system is deleting messages will not be affected.
From the Please select drop-down menu, select the type and start
the action by clicking on the Start button.
If you wish to actualize the SMTP/POP3 Proxy Content table, select
the Refresh proxy content table action from the Please select
drop-down menu.
Attention:
Messages of the selected type will be deleted without further
confirmation.
Filters
The Filters function allows you to filter E-Mails with specific attributes
from the table. The function facilitates the management of huge
networks, since the protocols of a specific type can be presented in a
concise way.
Filtering e-mails:
1.
Click on the Filters button.
The entry window will open.
2.
Enter the filter attributes in the following fields. Not all attributes
have to be defined.
Type: If you wish to filter e-mails of a specific type, select them
from the drop-down menu.
Status: If you wish to filter e-mails of a specific status, select
them from the drop-down menu.
254
Using the Security System
Content Filter Type: This drop-down menu allows you to filter
e-mails, that have been filtered by a specific function from the
Content-Filter-Modules.
Sender: This drop-down menu allows you to filter e-mails with a
specific sender address.
Recipient(s): This drop-down menu allows you to filter e-mails
with a specific recipient address.
3.
Click the Apply Filters button to start the filter.
In this case, only the filtered e-mails will be displayed in the table.
Once the menu has been left, all protocols will be displayed again.
255
Using the Security System
5.7. Virtual Private Networks
(IPSec VPN)
A Virtual Private Network (VPN) is a secure connection between
two networks over an untrusted network (such as the Internet).
VPNs are very useful when sensitive information must be transmitted
or received over the Internet. The VPN prevents third parties from
reading or modifying the information in transit. The connection is
controlled and secured by the software installed at the connection
endpoints. This software implements authentication, key exchange,
and data encryption according to the open Internet Protocol
Security (IPSec) standard.
Only authenticated computers can communicate through a VPNprotected connection. No other computer can transmit information
over this connection.
VPN connections can be established between two hosts, one host and
one network, or two networks. When one endpoint is a single computer, the VPN connection will extend all the way to that computer,
where the data is encrypted and decrypted. If one end point is a
network, the connection will end at a Security Gateway, which
manages the VPN functions for the rest of the network. The data
transmission within the network, between the security gateway and
client computers, is not encrypted.
Data transfer between two computers over a Public Wide Area
Network (WAN) uses public routers, switches, and other network
components. This is, in general, not secure as messages can be read
in clear text at every point between the end computers. An IPSec
VPN, however, builds a secured IP Security (IPSec) tunnel through
the public WAN. Messages sent through this tunnel cannot be read.
An IPSec tunnel consists of a two directional Security Associations
(SAs), one for each direction of communication.
An IPSec SA consists of three components:
256
Using the Security System
•
the Security Parameter Index (SPI),
•
the IP address of the receiver,
•
a Security Protocol Authentication Header (AH) or Encapsulated Security Payload (ESP).
With the help of the SA, the IPSec VPN tunnel has the following
features:
•
Data confidentiality through encryption
•
Data integrity through data authentication
•
Sender authentication through PSK, RSA, or X.509 certificates
The security features can be combined as desired. Most administrators use at least the encryption and authentication components.
There are a few scenarios where VPNs can be used:
257
Using the Security System
1. Net-to-Net Connection
In this scenario, one network communicates with another.
Two remote offices can use a VPN tunnel to communicate with each
other as though they were on a single network.
This kind of connection can also be used to allow trusted third companies (e.g., consultants and partner firms) access to internal
resources.
258
Using the Security System
2. Host-to-Net Connection
In this scenario a single computer communicates with a network.
Telecommuters can use VPN to communicate with the main office
securely.
3. Host-to-Host Connection
In this scenario one computer communicates with another computer.
Two computers can use a VPN tunnel to communicate securely over
259
Using the Security System
an untrusted network.
A VPN server is a cost effective and secure solution for transferring
sensitive data, and can replace existing expensive direct connections
and private lines.
The IPSec Concept
IP Security (IPSec) is a suite of protocols designed for cryptographically secure communication at the IP layer (layer 3). (see also
chapter 1, on page 9).
The IPSec standard defines two service modes and two protocols:
•
Transport Mode
•
Tunnel Mode
•
Authentication Header (AH) Authentication protocol
•
Encapsulated Security Payload (ESP) Encryption (and Authentication) protocol
IPSec also offers methods for manual and automatic management of
Security Associations (SAs) as well as key distribution. These
characteristics are consolidated in a Domain of Interpretation
(DOI).
Note:
This security system uses the Tunnel Mode and the Encapsulated
Security Payload (ESP) protocol.
260
Using the Security System
IPSec Modes
IPSec can work in either Transport Mode or Tunnel Mode. In
principle, a host-to-host connection can use either mode. If, however,
one of the endpoints is a security gateway, the Tunnel Mode must be
used. The IPSec VPN connections on this security system always use
the Tunnel Mode.
In
Transport
original
IP
Mode,
packet
is
encapsulated
in
packet.
original
The
the
not
another
IP
header is retained, and the
rest of the packet is sent
either in clear text (AH) or encrypted (ESP). Either the complete
packet can be authenticated with AH, or the payload can be
encrypted and authenticated using ESP.
In both cases, the original header is sent over the WAN in clear text.
In Tunnel Mode, the complete packet – header and
payload – is encapsulated in
a
new
IP
packet.
An
IP
header is added to the IPpacket, with the destination
address set to the receiving tunnel endpoint. The IP addresses of the
encapsulated packets remain unchanged. The original packet is then
encrypted and/or authenticated in its entirety. The AH protocol allows
the entire packet to be authenticated.
261
Using the Security System
IPSec-Protocols
IPSec uses two protocols to communicate securely on the IP level.
•
Authentication Header (AH) – a protocol for the authentication
of packet senders and for ensuring the integrity of packet data
•
Encapsulating Security Payload (ESP) – a protocol for encrypting the entire packet and for the authentication of its
contents.
Das Authentication Header-Protocol (AH) checks the authenticity
and integrity of packet data. In addition, it checks that the sender and
receiver IP addresses have not been changed in transmission. Packets
are authenticated using a checksum created using a Hash-based
Message Authentication Code (HMAC) in connection with a key. One
of the following hashing algorithms will be used:
Message Digest Version 5 (MD5) This algorithm generates a 128bit checksum from a message of any size. This checksum is like a
fingerprint of the message, and will change if the message is altered.
This hash value is sometimes also called a digital signature or a
message digest.
The Secure Hash (SHA-1) algorithm generates a hash similar to
that of MD5, though the SHA-1 hash is 160 bits long. SHA-1 is more
secure than MD5, due to its longer key.
Compared to MD5, an SHA-1 hash is somewhat harder to compute,
and requires more CPU time to generate. The computation speed
depends, of course, on the processor speed and the number of IPSec
VPN connections in use at the Security Gateway.
In addition to encryption, the Encapsulated Security Payload
Protocol (ESP) offers the ability to authenticate senders and verify
packet contents. If ESP is used in Tunnel Mode, the complete IP
packet (header and payload) is encrypted. New, unencrypted IP and
ESP headers are added to the encapsulating packet: The new IP
header contains the address of the receiving gateway and the address
262
Using the Security System
of the sending gateway. These IP addresses are those of the VPN
tunnel.
For ESP with encryption normally the following algorithms are used:
•
Triple Data Encryption Standard (3DES)
•
Advanced Encryption Standard (AES)
Of these, AES offers the highest standard of security. The effective
key lengths that can be used with AES are 128, 192 and 256 Bits.
This security system supports a number of encryption algorithms.
Either the MD5 or SHA-1 algorithms can be used for authentication.
Key Management
The secure generation, management, and distribution of keys is
crucial to the security of IPSec connections. IPSec supports both
manual and automatic key distribution.
Manual key distribution requires that both sides of the connection
be configured by hand. This means that for every Security
Association (SA) (there are two per tunnel), a Security Parameter
Index
(SPI)
must
be
selected,
a
key
for
encryption
and
authentication must be generated, and the keys must be installed on
both sides of the tunnel. These keys should also be changed at
regular intervals.
Clearly,
manual
distribution is labor-intensive.
Because of
the
complexity of the process, manual intervention intensifies the risk
that an unauthorized party gains access to the keys.
For these reasons, Manual Key Distribution is not often used.
The Internet Key Exchange (IKE) protocol provides IPSec with
automatic key management capabilities. Keys are automatically
generated and securely exchanged. IKE also allows the generation
and management of multiple VPN tunnels and the use of dynamic IP
addresses. The IKE protocol automatically manages the Security
Associations (SAs) for a connection.
263
Using the Security System
This system supports three kinds of authentication for IKE:
•
IKE with Preshared Keys (PSK)
•
IKE with RSA Keys (RSA)
•
IKE with X.509v3 Certificates (X.509)
Authentication with Preshared Keys (PSK) uses secret passwords as
keys – these passwords must be distributed to the endpoints before
the connection is built. When a new VPN tunnel is built, each side
checks that the other knows the secret password. The security of such
PSKs depends on how “good” the passwords used are: common
words and phrases are subject to dictionary attacks. Permanent or
long-term IPSec connections should use certificates or RSA keys
instead.
Authentication via RSA Keys is much more sophisticated. In this
scheme, each side of the connection generates a key pair consisting
of a Public Key and a Private Key. The private key is necessary for
the encryption and authentication during the Key Exchange. Both
keys are mathematically independent from each other and are in a
unique relation to each other: Data encrypted with one key can only
be decrypted with the other. The Private Key cannot be deducted
with maintainable work from the Public Key.
Both receivers of an IPSec VPN connection require in this authentication method their own Public Key and Private Key.
Similarly, the X.509 Certificate authentication scheme uses public
keys and private keys. An X.509 certificate contains the public key
together with information identifying the owner of the key. Such
certificates are signed and issued by a trusted Certificate Authority
(CA). During the Key Exchange process, the certificates are exchanged and authenticated using a locally stored CA certificate.
Further information on Certificate Authorities (CAs) can be found
in chapter 5.1.9 on page 94 and in chapter 5.7.6 on page 285.
264
Using the Security System
5.7.1.
Connections
The Connections menu allows you to configure local settings for new
IPSec VPN tunnels and to manage existing connections.
Global IPSec Settings
This section allows you to
enable
or
disable
the
IPSec VPN system by
clicking the Enable/Disable
button
next
to
Status.
IKE
Debugging:
function
allows
This
you
to
check the IPSec connection. Detailed information
is logged to the IPSec
logs. These protocols can
be displayed in real time
in the Local Log/IPSec
VPN
menu
or
down-
loaded to your local computer. Further information on the Local Logs menu can be found in
chapter 5.9 on page 302.
Important Note:
The IKE Debugging function requires a large amount of system
resources, and can slow the IPSec VPN connection building process
down considerably. This system should only be enabled when IKE is
actively being debugged.
265
Using the Security System
IPSec Connections
In the IPSec Connections table, all current VPN connections are
listed.
IPSec System Information
VPN Status: In the VPN
Status window, status information is shown for active encryption algorithms, all active IPSec connections, and detailed
information about every Security Association (SA).
VPN Routes: The VPN Routes window shows all active IPSec SA
connections. If no entries exist here, no IPSec connections are active.
Routing entries follow the following form:
A B
-> C
=> D
3 192.168.105.0/24 -> 192.168.104.0/24 => %hold
8 192.168.105.0/24 -> 192.168.110.0/24 => %trap
0 192.168.105.0/24 -> 192.168.130.0/24 =>
tun0x133a@233.23.43.1
Column A: The number of packets in this VPN connection.
Column B: The local subnet or host.
Column C: The remote subnet or host.
Column D: The status of the connection.
%trap: The connection is idle and is waiting for a packet. The status
initiates the end of the VPN connection.
%hold: The connection is being negotiated. All packets will wait until
the VPN tunnel is established (UP).
tun0x133a@233.23.43.1: Messages like these show that the tunnel
is up.
266
Using the Security System
A VPN tunnel with ID 0x133a has been established, and the IP
address of the Remote Endpoint is 233.23.43.1..
Example:
A B
-> C
=> D
23 192.168.105.0/24 -> 192.168.104.0/24 =>
tun0x1234@123.4.5.6
This message shows that 23 data packets have been sent from
network
192.168.105.0/24
to
network
192.168.104.0/24.
The
tunnel’s ID number is 0x1234, and the remote endpoint is has IP
address 123.4.5.6..
Configuring an IPSec Connection:
1.
Under the IPSec VPN tab, open the Connections menu.
2.
Enable the option by clicking the Enable in the Global IPSec
Settings window.
The New IPSec Connection window will open.
3.
In the Name field, enter a descriptive name for the new IPSec
VPN connection:
Name: Enter a descriptive name for this IPSec-VPN tunnel.
Allowed characters are: Only alphanumeric and underscore
characters are allowed.
Type: Choose the type of connection to use.
Use Standard for Net-to-Net connections.
The Road Warrior, Road Warrior CA and MS Windows L2TP
IPSec connection types are useful with HOST-to-NET connections, e.g. for sales representatives. The telecommuter will
then be able to build an IPSec connection to the firm’s internal
network. A road warrior connection can only be used through a
default gateway.
267
Using the Security System
Note:
Multiple remote key objects can be added to a single road
warrior connection. This can serve to reduce configuration
hassles. It must be respected, however, that all road warriors
use the same type of authentication (PSK, RSA or X.509) – a
mixed operation can result in malfunctions.
Further configuration parameters can be set for the chosen
connection type.
4.
Make the following basic settings for the IPSec-VPN connection.
IPSec Policy: The policy controls the parameters for the VPN
connection. This includes the settings for Key Exchange, IKE,
and the IPSec connection.
The drop-down menu contains a number of pre-defined policies.
You can define custom ones in the IPSec VPN/Policies menu.
Note:
A standard policy is used for the MS Windows L2TP IPSec
type of connection.
The configuration of IPSec Policies is detailed in chapter 5.7.2
on page 273.
Auto Packet Filter: Once the IPSec-VPN connection is successfully established, the packet filter rules for the data traffic will
automatically be added. After the completion of the connection,
the packet filter rules will be removed.
The Auto Packet Filter function is available for the Standard
and road warrior connection types.
268
Using the Security System
Security Note:
If you want greater control over the packet filter rules, or
wish to manage them in a more centralized way, disable
the Auto Packet Filter function and enter the rules manually in the Packet Filter/Rules menu.
Strict Routing: When this function is enabled (On), VPN Routing is not only done with the destination address, but in harmony
with the source and destination address.
If Strict Routing is enabled, it is possible to simultaneously set
encrypted and decrypted connections from different source
addresses to one network.
If the Strict Routing function is disbled (Off), further networks
and hosts can be connected to the IPSec-VPN tunnel through the
setting of Source NAT rules.
The Strict Routing function can only be disabled or enabled in
the Standard type of connection. For all other types of connections the function is always enabled!
5.
In the Endpoint Definition window, select the endpoint of the
IPSec tunnel.
Local Endpoint: Use the drop-down menu to select the local
endpoint. Always choose the network interface on the same side
of the firewall as the remote endpoint.
Remote Endpoint: Choose the IP address of the remote endpoint here.
With the Road Warrior or MS Windows L2TP IPSec types of
connection, the remote endpoint has always a dynamic IPaddress.
6.
The Subnet definition (optional) window allows you to set an
optional subnet for both endpoints.
Local Subnet: Choose the local subnet here.
Remote Subnet: Choose the remote subnet here.
269
Using the Security System
With a road warrior connection, only the local subnet can be
configured. This is no more possible if you additionaly enable the
L2TP Encapsulation function in step 7.
Note:
With the MS Windows L2TP IPSec connection this window will
not be displayed. The IPSec-VPN access will be managed
through the Packet Filter.
7.
Select the associated key in the Authentication of Remote
Station(s) window.
IPSec remote keys are defined in the IPSec VPN/Remote Key
menu. The settings in this window depend on the type of
connection.
7. 1 Standard
Key: Use the drop-down menu to select a Remote Key.
7.2 Road Warrior
L2TP Encapsulation: This drop-down menu allows you to
additionally enable L2TP over IPSec (On).
Keys: Select the Remote Keys for the road warrior connection
from the selection window.
7.3 Road Warrior CA
L2TP Encapsulation: This drop-down menu allows you to additionally enable L2TP over IPSec (On).
Use CA: With the road warrior CA connection type, the authentication is based on the Distinguished Name (DN) of the remote
receiver (Remote Endpoint). You thus need a Certificate Authority (CA) from this endpoint. Only the VPN Identifier X.509
DN can be used.
270
Using the Security System
From the drop-down menu, select X.509 DN Certificate
Authority (CA).
Client DN Mask: In order to use a Distinguished Name as an
ID, you will need the following information from the X.509 index:
Country (C), State (ST), Local (L), Organization (O), Unit (OU),
Common Name (CN) und E-Mail Address (E).
The data in this entry field must be in the same order as in the
certificate.
7.3 MS Windows L2TP IPSec
L2TP Encapsulation: With this type of connection, L2TP over
IPSec is automatically enabled (On).
IPSec Shared Secret: With the MS Windows L2TP IPSec connection type, the authentification is based on Preshared Keys.
Enter the password into this entry field.
8.
Save these settings by clicking Add.
The newly configured IPSec profile will appear, deactivated, at the
bottom of the table (status light is red). Clicking on the status light
enables the IPSec connection.
After you configure a new VPN tunnel, you will need to establish the
related packet filter rules to allow the two computers to communicate.
Configuring packet filter rules is described in chapter 5.4 on page
179.
271
Using the Security System
Example:
In order to set-up a Net-to-Net VPN connection (between network 1
and network 2), you will need to define the following rules:
1.
Under the Packet Filter tab, open the Rules menu.
2.
In the Add Rules window, add the following rule for network 1:
Source: Network1
Service: Any
Destination: Network 2
Action: Allow
3.
Confirm the entries by clicking on Add Definition.
4.
In the Add Rules window, add the following rule for network 2:
Source: Network 2
Service: Any
Destination: Network1
Action: Allow
5.
Confirm the entries by clicking on Add Definition.
These rules will allow complete access between the two networks.
272
Using the Security System
5.7.2.
Policies
In the Policies menu, you
can customize parameters
for IPSec connections and
collect them into a policy.
Policies are used to define
IPSec
contain
connections,
and
the configuration
of the selected key exchange method, IKE, and
the IPSec connection.
The chosen key exchange
method defines how the
keys for the connection are
to be managed.
The two exchange methods are:
•
Manual Key Exchange
•
Internet Key Exchange (IKE)
Because of the complexity of manual exchange, this system only
supports the IKE key exchange method. Manual exchange is not
allowed.
273
Using the Security System
Configuring an IPSec Policy:
1.
Under the IPSec VPN tab, open the Policies menu.
2.
Click New to open the New IPSec Policy menu.
3.
In the Name field, enter a name for the new policy:
Name: Enter a name describing the policy. It may be useful to
include the encryption algorithm in the name. The name can also
be defined as the last step in creating the policy.
Key Exchange: Only IKE is supported.
4.
In the ISAKMP (IKE) Settings window, configure the settings
for IKE:
IKE Mode: The IKE mode is used to support key exchange. At
the moment, only the Main Mode is supported.
Encryption Algorithm: The encryption algorithm is the algorithm used to encrypt IKE connections. The IPSec VPN function
of this security system supports 1DES 56bit, 3DES 168bit,
AES (Rijndael) 128bit, AES Rijndael 192bit, AES Rijndael
256bit, Blowfish, Serpent 128bit and Twofish.
Authentication Algorithm: The hashing algorithm ensures the
integrity of the IKE messages. The MD5 128bit, SHA1 160bit,
SHA2 256bit and SHA2 512bit algorithms are supported. The
algorithm used is determined by the remote endpoint of the
IPSec connection.
Important Note:
The SHA2 256bit and SHA2 512bit algorithms require a great
deal of system resources.
IKE
DH
Group:
The
IKE
group
(Diffie-Hellmann
group)
describes the kind of asymmetric encryption used during key
exchange. The IPSec VPN system on this security system
supports the Group 1 (MODP768), Group 2 (MODP 1024),
Group 5 (MODP 1536), Group X (MODP 2048), Group X
274
Using the Security System
(MODP 3072) and Group X (MODP 4096) protocols. The
group used is determined by the remote endpoint.
SA lifetime (secs): This option allows you to set the lifetime of
IKE sessions in seconds. This is set by default to 7800 seconds
(2h, 10 min).
In general, times between 60 and 28800 seconds (1 min to 8
hours) are allowed.
5.
In the IPSec Settings window, configure the settings for the
IPSec connection:
IPSec Mode: This system only supports tunnel mode.
IPSec Protocol: This system only supports ESP.
Encryption Algorithm: Choose the encryption algorithm to use
here. The IPSec VPN function of this security system supports
1DES 56bit, 3DES 168bit, AES (Rijndael) 128bit, AES
Rijndael 192bit, AES Rijndael 256bit, Blowfish, Serpent
128bit and Twofish. If you wish to create IPSec connections
without encryption, choose null here.
Authentication Algorithm: The MD5 128bit, SHA1 160bit,
SHA2 256bit and SHA2 512bit algorithms are supported. The
algorithm used is determined by the remote endpoint of the
IPSec connection.
Important Note:
The SHA2 256bit and SHA2 512bit algorithms require a great
deal of system resources.
SA Lifetime (secs): This option allows you to set the lifetime of
the IPSec connection. This is set by default to 3600 seconds
(1h). In general, times between 60 and 28800 seconds (1 min to
8 hours) are allowed.
PFS: The IPSec key used for VPN connections is generated from
random numbers. When Perfect Forwarding Secrecy (PFS) is
enabled, the system will ensure that the numbers used have not
275
Using the Security System
already been used for another key, such as for an IKE key. If an
attacker discovers or cracks an old key, he or she will have no
way of guessing future keys.
The IPSec VPN system on this security system supports the
Group 1 (MODP768), Group 2 (MODP 1024), Group 5
(MODP 1536), Group X (MODP 2048), Group X (MODP
3072) and Group X (MODP 4096) protocols. If you do not
wish to use PFS, select No PFS.
By default, this is set to Group 5 (MODP 1536).
Important Note:
PFS requires a fair amount of processing power to complete the
Diffie-Hellmann key exchange. PFS is also often not 100%
compatible between manufacturers. In case of problems with
the firewall’s performance or with building connections to
remote systems, you should disable this option.
Compression: This algorithm compresses IP-packets before
they are encrypted, resulting in faster data speeds.
This system supports the Deflate algorithm.
6.
If you have not yet named this policy, scroll back to the Name
field and enter one now.
7.
Create the new policy by clicking Add.
The new policy will appear in the IPSec Policies table.
276
Using the Security System
5.7.3.
Local Keys
The
Local
Keys
menu
allows an administrator to
manage
local
X.509
certificates, to define the
local IPSec identifier, and
to generate a local RSA
key pair.
Local IPSec X.509 Key
In this window, you can define keys for X.509 certificates provided
you have already generated these certificates in the IPSec VPN/CA
Management menu.
Chapter 5.7.6 on page 285 describes the process of generating X.509
certificates.
If you wish to use X.509 authentication, use the Local certificate
drop-down menu to select the certificate. This menu only contains
those certificates for which the associated private key is available.
In the Passphrase field, enter the password used to secure the
private key.
The active key will appear with its name in the Local IPSec X.509
Key window. If you choose a new local key, the old key will
automatically be replaced.
The firewall will use the ID and public/private keypair of the current
local Local X.509 key to sign, authenticate, and encrypt X.509 IPSec
key exchanges.
277
Using the Security System
RSA Authentication
RSA authentication requires a Local IPSec Identifier and a Local
RSA Key.
Note:
Depending on the selected key length and the processor of the
security solution, the generation of RSA keys can take several
minutes.
1.
In the Local IPSec RSA Key window, define a unique VPN
Identifier.
IPv4 Address: For static IP addresses.
Hostname: For VPN security gateways with dynamic addresses.
E-Mail Address: For mobile (road warrior) connections.
Save the settings by clicking Save
2.
Generate a new RSA Key in the Local RSA Key window, by
selecting the key length from the RSA Key length drop-down
menu.
3.
When you click Save, the system will begin generating a new
RSA key pair.
After generation, the active Local RSA Key and its name will be
displayed. When a new key is generated, the old key will be replaced.
278
Using the Security System
PSK Authentication
For authentication through Preshared Keys (PSK), no additional
configuration of local keys is required.
During the key exchange using IKE Main Mode, only IPv4
Addresses are supported as IPSec identifiers. The IPSec identifier in
the IKE Main Mode is automatically encrypted with the PSK, and so
PSK cannot be used for authentication. The IP addresses of IKE
connections are automatically used as IPSec identifiers.
The PSK Key is entered in the IPSec Policies/Remote Keys menu.
It will automatically be used as the Local PSK Key as well.
279
Using the Security System
5.7.4.
Remote Keys
IPSec remote key objects
can
be
defined
in
the
Remote Keys menu. An
IPSec-Remote-Key-Object
represents an IPSec receiver. This receiver can
either be a security gateway, a host or also a road warrior with dynamic IP-address.
An IPSec remote key object is defined by three parameters:
•
The IKE authentication method (PSK/RSA/X.509)
•
The IPSec ID of the remote endpoint (IP/Hostname/E-Mail Address/Certificate)
•
The authentication data (Shared secret for PSK, public key for
RSA, X.509 certificate)
Every IPSec remote endpoint must have an associated IPSec remote
key object defined.
Defining IPSec Remote Keys:
1.
Under the IPSec VPN tab, open the Remote Keys menu.
The New Remote IPSec Key will immediately be displayed.
2.
In the Name field, enter a name for the new Remote Key.
Virtual IP Key If you wish to use the IPSec Remote Key for a
standard connection, continue with step 3.
Virtual IP Key (optional): This function allows you to assign a
virtual IP address to the road warrior. This is the only way to
manually set IP addresses for such connections. If you enter an
IP address here, it must also be configured on the road warrior
system.
280
Using the Security System
Attention:
With a road warrior IPSec tunnel, the Virtual IP Key function
must be enabled if you wish to use the NAT Traversal function
and the L2TP Encapsulation function is disabled.
The IP address entered here should not be used anywhere else,
and cannot be a part of a directly connected network.
3.
Use the Key type drop-down menu to select the IKE authentication method. Further options are available depending on the
chosen Key type.
PSK: The firewall only supports using IPv4 Addresses as VPN
Identifiers during the key exchange phase of IKE Main Mode.
Enter the shared password in the Preshared Key field.
If you wish to configure many road warrior connections, you only
need one PSK for all connections.
Security Note:
Use a secure password! Your name spelled backwards is,
for example, not a secure password – while something like
xfT35$4 would be. Make certain that this password does
not fall into the wrong hands. With this password, an
attacker can build a VPN connection to the internal
network. We recommend changing this password at regular
intervals.
RSA: The key pair consists of a private key and a public key.
In order for the endpoints to communicate, they must exchange
their public keys. Public keys can be exchanged via e-mail.
In the VPN Identifier drop-down menu, choose the VPN ID type
of the endpoint. If you select E-Mail Address, Full qualified
domain name or IP Address, you must enter the address or
name in the entry field below.
X509: Use the VPN Identifier drop-down menu to select the
kind of VPN ID to use. If you select E-Mail Address, Full
281
Using the Security System
qualified domain name or IP Address, you must enter the
address or name in the entry field below.
In order to use a Distinguished Name as an ID, you will need
the following information from the X.509 index: Country (C),
State (ST), Local (L), Organization (O), Unit (UO), Common
Name (CN) und E-Mail Address (E-Mai).
4.
To save the new IPSec remote key object, click Add.
The new remote key object will appear in the Remote Keys table.
CA Management Remote Keys are shown in a separate table.
282
Using the Security System
5.7.5.
L2TP over IPSec
L2TP over IPSec is a combination of the Layer 2 Tunneling Protocol
and of the IPSec standard protocol. L2TP over IPSec allows you,
while providing the same functions as PPTP, to give individual hosts
access to your network through an encrypted IPSec tunnel. On
Microsoft Windows systems, L2TP over IPSec is easy to set-up, and
requires no special client software.
For the MS-Windows systems 98, ME and NT Workstation 4.0,
Microsoft L2TP/IPSec VPN Client must first be installed. This
client is available from Microsoft at:
http://www.microsoft.com/windows2000/server/evaluation/news/bull
etins/l2tpclient.asp
L2TP over IPSec Settings
Authentication: Use this
drop-down menu to configure the authentication
method. If you have defined a RADIUS server in the System/User
Authentication menu, you can use it here as well.
The configuration of the Microsoft IAS RADIUS server and the
configuration of RADIUS within WebAdmin is described in chapter
5.1.7 on page 71.
Debugging: This function allows you to check the L2TP-over-IPSec
connection. Detailed information is logged to the IPSec logs. These
protocols can be displayed in real time in the Local Log/Browse
menu or downloaded to your local computer. Further information
about the Local Logs menu can be found in chapter 5.9 on page 302.
283
Using the Security System
L2TP over IPSec IP Pool
This
menu
is
used
to
define which IP addresses
PPTP
hosts
should
be
assigned to. By default, a
network from the private
IP range 10.x.x.x will be selected when the L2TP-over-IPSec function
is enabled for the first time. This network is referred to as IPSec
Pool and can also be used for all other functions of the Security
system, using network definitions. If you wish to use a different
network, simply change the definition of the IPSec-Pool, or assign
another defined network as IPSec-Pool here.
Note:
If you use private IP addresses for your IPSec Pool, such as the
pre-defined network and you wish IPSec hosts to be allowed to
access the Internet, appropriate Masquerading or NAT rules must
be in place for the IPSec Pool.
L2TP over IPSec Client Parameters
This window allows you to
define DNS and WINS servers which should be assigned to hosts when the
connection is established.
284
Using the Security System
5.7.6.
CA Management
A Certificate Authority (CA) certifies the authenticity of public
keys. This ensures that the certificate used in a VPN connection really
belongs to the endpoint, and not to an attacker. The CA Management menu allows you to create and manage your own X.509
Certificate Authority (CA). The authority will verify the validity of
X.509 certificates exchanged during IPSec VPN connections. The
relevant information is stored in the X.509 certficates.
But you can also use certificates, signed by commercial providers,
such as VeriSign.
Note:
Every certificate has unique CA with respect to its identifying
information (Name, Firm, Location, etc.). If the first certificate is lost,
a second cannot be generated to replace it.
The CA Management menu allows you to manage three distinct
kinds of certificates, which are used for different purposes. The three
certificates differentiate themselves according to use, and, importantly, whether or not the Private Key is stored:
CA (Certificate Authority) Certificate: If a CA is saved without
private key, it can be used for the authentication of the host and
user certificate of incoming IPSec connections: this type of CA is
called a Verification CA.
If a CA saves its private key, it can be used to sign certificate
queries, in order to produce a valid certificate. This CA is called a
Signing CA.
The system can contain a number of Verification CAs, but only one
Signing CA.
Host CSR (Certificate Signing Request): This is a request to have
a certain certificate signed. When it is given to a Signing CA - and
the CA verifies the identity of the owner – the CA sends back a fullyformed and signed Host Certificate.
285
Using the Security System
Host Certificate: This certificate contains the public key of the host
as well as identifying information about the host (such as IP address
or owner). The certificate is also signed by a CA, verifying that the
key does indeed belong to the entity named in the identification
information. These valid certificates are used to authenticate remote
IPSec hosts/user endpoints.
The drop-down menu at
the bottom of the table
allows you to download
certificates in various formats, or to delete certificates from the system:
PEM: A format encoding the certificate in ASCII code. The certificate,
request, and private key are stored in separate files.
DER: A binary format for encoding certificates. The certificate, request, and private key are stored in separate files.
PKCS#12: A “container file”. One file can contain the certificate,
private key, and verification CA.
Delete: Delete the specified certificate.
Issue CERT from CSR: This function signs a CSR, generating a full
host certificate.
286
Using the Security System
Generating a Client/Host Certificate:
Step 1: Create a Signing CA.
1.
Under the IPSec VPN tab, open the CA Management menu.
2.
In the Certificate Authorities table, click the New button.
The Add Certificate Authority window will open.
3.
Select the Generate option.
4.
In the Name field, enter a descriptive Name for the certificate
authority.
Allowed characters are: Only alphanumeric and underscore
characters are allowed.
5.
Enter
a
password
with
at
least
four
characters
in
the
Passphrase field.
6.
Use the Key Size drop-down menu to select the desired key
length.
7.
Use the drop-down menus and entry fields from Country to EMail Address to enter identifying on the CA.
8.
To save the entries, click the on the Start button.
The Signing CA will be loaded into the Certificate Authorities
menu. This CA will answer CSR requests by generating new host
certificates.
Step 2: Generate a Certificate Request.
1.
In the Host CSR or Certificate table, click the New button.
The Host CSR or Certificate window will open.
2.
Select the Generate CSR option.
In the VPN ID drop-down menu, select the type of VPN ID to
use. If you select E-Mail Address, Hostname or IPv4
Address, you must enter the relevant information in the field at
287
Using the Security System
right.
The field should be empty if you select the X509 DN option.
3.
In the Name field, enter a descriptive name for this certificate
request.
Allowed characters are: Only alphanumeric and underscore
characters are allowed.
4.
Enter
a
password
with
at
least
four
characters
in
the
Passphrase field.
5.
Use the Key Size drop-down menu to select the desired key
length.
6.
Use the drop-down menus and entry fields from Country to EMail
Address
to
enter
identifying
information
about
the
certificate holder.
Common Name: If the CSR is for a road warrior connection,
enter the name of the user here. If the CSR is for a host, enter
the hostname.
7.
To save the entries, click the on the Start button.
The Certificate Request CSR + KEY will appear in the Host CSRs and
Certificates table. The table will also show the type, name, and VPN
IP of the CSR. The request can now be signed by the Signing CA
created in the first step.
Step 3: Generate the Certificate.
1.
In the Host CSRs and Certificates table, select the CSR + KEY
certificate request.
2.
Use the drop-down menu at the bottom of the table to select the
Issue CERT from CSR function.
An entry field labeled Signing CA Passphrase will appear.
Enter the password of the Signing CA here.
3.
288
Click Start.
Using the Security System
From the CSR + KEY, the CA will generate the CERT + KEY
certificate: the certificate will replace the CSR in the table.
Step 4: Download the Certificate.
1.
In the Host CSRs and Certificates, select the new certificate.
2.
Use the drop-down menu at the bottom of the table to select a
download format.
DER: In the Passphrase field, you must enter the password of
the Private Key.
PEM: No password is necessary.
PKCS#12: Enter the password of the Private Key in the
Passphrase field. In the Export Pass field, enter a different
password. This password will be required to install the certificate
on the client computer.
3.
Click Start.
You must now install the certificate on the remote computer. The
installation process depends on the IPSec software on that computer.
289
Using the Security System
5.7.7.
Advanced
This menu allows you, to
make
additional
settings
for the IPSec VPN option.
This should, however, only
be done by experienced
users.
NAT
Traversal:
enabled,
When
NAT Traversal
allows hosts to establish an
IPSec tunnel through NAT devices. This module attempts to detect if
NAT firewalls are being used between the server and client: if so, the
system will use UDP packets to communicate with the remote host.
Please note that both IPSec nodes must support NAT traversal, and
that road warrior nodes must be configured with a virtual IP address.
In addition, IPSec passthrough must be turned off on the NAT
device(s), as this can break NAT traversal.
Important Note:
You cannot use local IP addresses for the Virtual IP address,
because the security system does not answer ARP requests for these.
Copy TOS Flag: Type-of-Service-Bits (TOS) are several four Bitflags in the IP-header. The Bits are referred to as Type-of-ServiceBits, as they allow the transferring application, to tell the network
which type of service quality is necessary. The available service
quality classes are: minimum delay, maximum throughput, maximum
reliability and minimum cost.
This function copies the content of the Type-of-Service field in the
encrypted data packet, so that the IPSec data traffic can be routed
according to its priority.
Enable the Copy TOS Flag function by clicking on the Enable button.
290
Using the Security System
Send ICMP Messages: If a data packet overwrites the configured
MTU value, the system will send an ICMP message to the source
address: Destination unreachable/fragmentation needed.
This allows for using Path MTU Discovery.
Automatic CRL Fetching: There might be situations, in which the
provider of a certificate attempts to revoke the confirmation awarded
with still valid certificates, for example if it has become known that
the receiver of the certificate fraudulently obtained it by using wrong
data (name, etc.) or because an attacker has got hold of the private
key, which is part of the certified public key. For this purpose, socalled Certificate Revocation Lists or CRLs are used. They normally
contain the serial numbers of those certificates of a certifying
instance, that have been held invalid and that are still valid according
to their respective periods of validity.
After the expiration of this periods the certificate will no longer be
valid and must therefore not be maintained in the block list.
The Automatic CRL Fetching function automatically requests the
CRL through the URL defined in the partner certificate via HTTP,
Anonymous FTP or LDAP Version 3. On request, the CRL can be
downloaded, saved and updated, once the validity period has expired.
Enable the function by clicking on the Enable button (status light is
green).
Please, check if the packet filter rules in the Packet Filter/Rules
menu are configured such that the CRL Distribution Server can be
accessed.
Strict CRL Policy: Any partner certificate without a corresponding
CRL will be rejected.
Enable the function by clicking on the Enable button (status light is
green).
291
Using the Security System
Send ICMP Messages: If a data packet exceeds a set MTU value,
the system will send the following ICMP message to the source
address: Destination unreachable/fragmentation needed.
This allows for the use of Path MTU Discovery.
IKE debug Flags: This selection field allows you to configure the
scope of IKE-debugging logs. The IKE Debugging function must be
enabled in the IPSec VPN/Connections menu.
The following flags can be logged:
•
State Control: control messages on the IKE status
•
Encryption: Encryption and decryption operations
•
Outgoing IKE: Content of outgoing IKE messages
•
Incoming IKE: Content of incoming IKE messages
•
Raw Packets: message in unprocessed bytes
MTU: Enter a the MTU value in this entry field.
By default the MTU value is already defined: 1420 Byte.
292
Using the Security System
5.8. System Management (Reporting)
The Reporting function provides current information about the system, the state of various subsystems, and real-time information about
various reporting functions. The displayed values are updated every
five minutes.
The diagrams shown on the first page of the Reporting menus show
an overview of the current day’s activity. By clicking the Show all …
button you can open a page containing graphics built from weekly,
monthly, and yearly statistics.
5.8.1.
Administration
The Administration menu
contains an overview of the
administrative events of the
last 30 days.
The following events will be displayed:
•
WebAdmin Logins
•
Remote Logins
•
Local Logins
•
System Up2Dates
•
Virus Pattern Up2Dates
•
Intrusion Protection Pattern Up2Dates
293
Using the Security System
•
Config Changes
•
Astaro Configuration Manager Uploads
•
System Restarts
•
High Availability Takeover
5.8.2.
Virus
The Virus menu contains an
overview
of
the
filtered
viruses of the last 7 days.
The following viruses will be displayed:
•
SMTP Viruses
•
POP3 Viruses
•
SMTP Viruses
5.8.3.
Hardware
This menu shows the current values relating to your
system hardware. The system collects statistics about
CPU utilization, RAM utilization, and swap utilization.
The security system collects
graphics and statistics every
five minutes and updates
them. The information can
also be updated manually
by clicking on the Reload button. Don’t use the Refresh button of
the browser, because this will log you out of the WebAdmin
configuration tool!
294
Using the Security System
CPU Load (Daily Graph): This diagram shows the current utilization
of the CPU.
Memory Usage (Daily Graph): The current RAM utilization statistics
are shown here. When more functions and subsystems are enabled on
the firewall, more RAM will be required to support them.
SWAP Usage (Daily Graph): This diagram shows the current
amount of swap space being used. Swap space is used to supplement
RAM: if your system is running out of available RAM, you will see a
sharp increase in swap usage.
5.8.4.
Network
This menu shows current
statistics relating to network
traffic.
These
dia-
grams will not be useful
unless the network cards
have been correctly configured in the Network/
Interfaces menu.
The configuration process
for network cards is described in chapter 5.3.2 on
page 119.
295
Using the Security System
5.8.5.
Packet Filter
Packet
filter
violations
in
diagrams will be displayed in
a graphic in this menu. The
rule violations will also be
logged to the Packet Filter
Logs.
The
log
files
are
saved to the Local Logs/
Browse menu.
5.8.6.
Content Filter
The processed data and actions of the Content Filter, relating to the
HTTP, SMTP and POP3 proxies will be displayed in the form of tables
and diagrams in this menu. The Spam Protection option and the
Spam Score are described in chapter 5.6.6.2 on page 247.
Information on the SMTP and POP3 proxies:
•
Sum of the treated messages
•
The average size of messages in kilobytes
•
The average height of Spam Score
Information on the HTTP proxy:
•
Sum of requested HTTP-sites
•
Sum of the HTTP-sites, blocked by Spam Protection
Sum of the HTTP-sites, blocked by Virus Protection
296
Using the Security System
5.8.7.
PPTP/IPSec VPN
The PPTP and IPSec-VPN connections will be displayed in a graphic
this menu.
5.8.8.
Intrusion Protection
Intrusion Protection events will be displayed in a graphic in this menu.
5.8.9.
DNS
The DNS-Query-statistic is represented in this menu.
5.8.10. HTTP Proxy Usage
The access to the HTTP-Proxy is recorded in this menu.
5.8.11. Executive Report
In the Executive Report menu, a complete report is created from
the individual reports in the Reporting tab.
Daily Executive Report by E-Mail
Once a day an updated
complete report is sent to
the e-mail addresses entered into the ordered list. The function is automatically enabled,
once an address has been entered into the field.
New e-mail addresses are taken over to the ordered list by the entry
field, by clicking on the Add button.
Ordered Lists are described in chapter 4.3.4 on page 39.
297
Using the Security System
Current Report
Clicking
on
the
Show
button opens a window, in
which the current complete
report
is
displayed.
This
report can be printed out by
clicking on the Print this
Report button.
5.8.12. Accounting
The
Accounting
monitors
all
IP
function
packets,
transmitted over the various
network cards and, once a
day, summarizes their size.
Statistics for the preceding
month are also generated at the beginning of each new month. These
statistics are then used to generate a report. This report is useful, for
instance, when an organization pays its service provider based on the
volume of data transmitted.
Accounting is configured and enabled in the Network/ Accounting
menu. Further information is available in chapter 5.3.7 on page 175.
Browse Accounting Reports: The existing accounting protocols will
be displayed in this window. Select the month from the Select
Report drop-down menu. The report will appear in the window below.
298
Using the Security System
Use the Log Files/Accounting menu to download or delete reports.
Report for current Month: This window displays the accounting
report for the current month.
Configuring Accounting:
1.
Under the Reporting tab, select the Accounting menu.
2.
Enable the Accounting Reports subsystem by clicking the
Enable button.
The entry window will open.
3.
Use the selection field in the Queried networks window to
select the networks for which detailed reports should be
generated. This will usually include your LAN and/or DMZ
networks.
Please see chapter 4.3.2 on page 36 for a description of how to
use selection fields.
Important Note:
Do NOT use the "Any" network, since it will match all source and
destination networks, meaning no traffic will be counted in the
report!
The changes will be applied immediately, and the networks will
appear in the Queried networks window.
299
Using the Security System
5.8.13. System Information
This menu offers additional
system information. This information will be displayed
in a separate window. Clicking on the Show button
opens this window.
Disk Partition: This table
lists the disk partitions on
the system and their usage
levels.
Process list: This tree lists
all current processes on the
Internet security system.
Interface Information: All
configured
internal
and
external network cards are
listed here.
300
Using the Security System
ARP Table: This table displays the current ARP cache of the system.
It lists all known associations between IP addresses and hardware
(MAC) addresses.
Local
Network
Connec-
tions: This table lists all
current network connections
to the firewall. Connections
through the firewall are not
shown.
301
Using the Security System
5.9. Local Logs (Log Files)
The logs, generated by the system will be managed in the Local Logs
tab.
5.9.1.
Settings
Configure the basic settings
for the creation of log files
in the Settings menu.
Status: Click the Enable button to enable the function (status light
shows green).
Important Note:
When this function is disabled, the Internet security system will not
create Log Files!
Local Log File Archives: This function locally stores generated log
files to the Security system. Configure the settings for the local log
file archive in the Local Log File Archive window.
By default, this function is enabled automatically, once the logging
functions are enabled.
Remote Log File Archives: This function allows you, to save the
generated log files to a remote host or server. The settings for the
automization of the log file archive on a separate server are
configured in the Remote Log File Archive.
302
Using the Security System
Local Log File Archive
This window allows you to
observe the utilization of the
local log file partition. The
diagram first displays the
used disk space in MB as
well as the utilization of the
partition in percent.
In the lower window, select
from the drop-down menu,
how the system has to react
if a specific part of the partition is overloaded with log files. Three
levels with different actions can be selected here.
Configuring the Log Files Level:
For each level, the following settings can be configured:
When Usage reaches: Configure here, at which utilization in percent
of the system partition an action will be executed.
do this: Configure the action in this selection menu.
The following actions can be configured:
•
Delete oldest Log Files: The oldest log files will automatically be
deleted by the Security system. The administrator previously
receives the WARN 711 notification e-mail.
•
Send Notification: Only the INFO 710 notification e-Mail with the
correspondent warning will be sent to the administrator.
•
Shut down System: The security system will automatically shutdown. The administrator receives the CRIT 712 notification e-Mail
before.
•
Nothing: No actions will be started.
303
Using the Security System
Save the settings by clicking on the Save button.
Remote Log File Archive
In this window configure the
settings for a remote log
files archive. If the Remote
Log File Archive is on a server, you must first add it to
the Definitions/Networks
menu.
Configuring Remote Log File Archive:
1.
In the Global Settings window, enable the Remote Log File
Archives function by clicking on the Enable button.
The Remote Log File Archive window will open.
2.
Use the Type drop-down menu to select the archiving type.
The drop-down menus and/or entry fields for the selected
archiving type will be displayed.
3.
Configure the settings for the archiving type.
3.1 FTP Server
Host: Use the drop-down menu to select a host.
Port: Use the drop-down menu to select a port.
By default, FTP is already selected.
Username: Enter a username in the entry field.
Password: Enter the password in this entry field.
Remote Path: Enter the path in the entry field.
304
Using the Security System
3.2 SMB (CIFS) Share
Host: Use the drop-down menu to select a host.
Username: Enter a username in the entry field.
Password: Enter the password in this entry field.
Share Name: Enter the share name in the entry field.
3.3 Secure Copy (SSH) Server
Public DSA Key: The Public DSA Key is displayed in this
window.
Host: Use the drop-down menu to select a host.
Username: Enter a username in the entry field.
Remote Path: Enter the absolute path in the entry field.
3.4 Send by E-Mail
E-Mail Address: Enter the e-Mail address into this entry field.
4.
Save your changes by clicking Save.
305
Using the Security System
5.9.2.
Local Log File Query
The Local Log File Query
action allows you, to search
for specific Log Files in a
local
archive.
The
search
result will be displayed in a
separate window.
Starting searches:
1.
In the Time Span drop-down menu select the time span.
2.
In the selection field Logs, choose the protocols.
Please see chapter 4.3.2 on page 36 for a description of how to
use selection fields.
3.
In the Mode drop-down menu, select the mode.
4.
If you are looking for protocols with specific strings, enter the
strings into the Search Term entry field.
5.
Begin the search by clicking seek.
The protocols will be listed in a separate window.
306
Using the Security System
5.9.3.
Browse
Each protocol is contained in the Browse menu. If this menu is
opened, the protocol groups (logs) will be displayed in the Browse
Local Log Files overview.
The Log File Overview
All protocol groups (logs) are contained in this overview. The groups
with the current protocols can directly be opened from this overview.
The functions from the left to the right:
Selection box: This setting is required in connection with the dropdown menu at the footer of the table. Select the protocol groups and
then choose the action (Delete or Download as ZIP File) from the
drop-down menu.
The action will start immediately.
Clicking on the selection box in the header selects all protocol groups.
307
Using the Security System
(
): Clicking on the trash can icon deletes a group from the table.
Name: All protocols are listed in alphabetical order in this column.
Date: The date of current protocols will not be displayed.
(
): Clicking on the folder icon opens the sub-tab with all protocols
of this group.
By clicking again on the icon, you will get back to the overview. The
additional functions in the sub-tab are described in the „Log File Subtab“ section.
File Count/Name: The number of existing files will be displayed in
this column. The old protocols can be opened from the sub-tab.
Activity: If the protocols in a group have been logged since Midnight,
a correspondent message will be displayed:
•
Now: The protocols are being generated right now.
•
Today: Protocols have been generated since Midnight.
Open the protocols by clicking on the message Now or Today. Open
the current protocol (Live Log) by clicking on the message Now or
Today (see left-hand picture).
Size: The size of the log file group will be displayed in this column.
(
): Clicking the download icon will allow you to download this Log
File to your local client computer. You can then use these Log Files
to import data into another program, for example Microsoft Excel.
308
Using the Security System
The Log File Sub-Tab
All protocols (Logs) of a group are listed in this sub-tab. The subgroup can be opened in the overview by clicking on the folder icon
(
).
The following additional functions are available in the sub-tab:
Date: For older protocols, listed in the sub-tab the date and time will
be displayed.
(
(
): Return to the overview by clicking on the folder icon.
): This is today's protocol. Clicking on the icon opens the Live
Log window.
(
): This in an archived protocol. Clicking on the symbol opens the
Log window.
File Count/Name: In the protocol from today, the path to the log
file and the Live Log message will be displayed in this column.
In this column, the file names will be displayed next to the archived
log files.
309
Using the Security System
Filters
The Filters function allows you to filter Log Files with specific
attributes from the table. This function enhances the management of
huge networks, as log files of a specific type can be presented in a
concise form.
Filtering Log files:
1.
Click on the Filters button.
The entry window will open.
2.
Enter the filter attributes in the fields. Not all attributes have to
be defined.
Group: If you wish to filter the log files of a specific group,
select it from the drop-down menu.
Month: This drop-down menu allows you to filter log files by a
given month.
Type: This drop-down menu allows you to filter log files by a
specific type.
3.
To start the filter click on the Apply Filters button.
Only the filtered log files will be displayed in the table. Next time
when you open the menu, the complete log file table will be
displayed.
310
Using the Security System
5.9.3.1.
Log Files
This chapter contains all available logs. These log files will only be
displayed in the Browse menu, if the correspondent processes have
been recorded by the System. The following Accounting data log
file, for example, will only be displayed, once the Accounting
function has been enabled in the Network/Accounting menu.
Accounting data: These log files contain all Accounting logs,
archived by the system. The Reporting/Accounting menu allows
you to view the current logs.
Astaro Configuration Manager: If the Internet security system is
configured remotely via the Astaro Configuration Manager, the
correspondent processes will be logged to these log files.
Astaro User Authentication: The activities of the AUA Daemon are
logged to these log files. AUA is used as the central authentication
daemon for various services.
Boot messages: The boot messages are recorded to these log files.
Configuration daemon: The activities of the AUA Daemon are
logged to these log files. The log files belong to the support logs and
will only be displayed after clicking on the show support logs
button.
Content Filter: The activities of the content filters on the HTTP,
SMTP and POP3 Proxies are logged to these log files.
DHCP client: If the interfaces are automatically assigned to IPaddresses on the Internet security system, the activities are recorded
to these log files.
DHCP server: If the Internet security system is used as DHCP-server
and assigns dynamic IP addresses to the clients in the network, the
activities are recorded to these log files.
Fallback archive: These log files are used as a security archive for
logged processes, which cannot be assigned to one of the log files.
311
Using the Security System
The log files belong to the support logs and will only be displayed
after clicking on the show support logs button. In general, those log
files are empty.
High Availability: The activities of the High-Availability-(HA)
system are logged to these log files.
HTTP daemon: The log files for the HTTP daemon belong to the
support logs and will only be displayed after clicking on the show
support logs button.
WebAdmin access: The requests to the user data base are recorded
to these log files.
Intrusion Protection: The activities of the Intrusion Protection
System (IPS) are recorded to these log files.
IPSec VPN: Extensive information on the configuration of the IPSecVPN and L2TP-over-IPSec-connections is recorded to these log
files. And also information on the Key Exchange and Encryption.
Virus Protection: The activities of the Virus Protection System
are recorded to these log files.
Kernel: The Kernel logs record the system status, including messages from device drivers, messages relating to the boot process, and
information about blocked packets.
Logging: The local archives of the log files on the Internet security
system and the forwarding of files to the Remote-Log-File-Archive are
recorded to these log files.
Local login: Information on the log-in processes to the local console
is recorded to these log files.
MiddleWare: The activities of the MiddleWare are recorded to these
log files. The log files belong to the support logs and will only be
displayed after clicking on the show support logs button.
Network accounting daemon: The efficiency of the accounting is
recorded to these log files.
312
Using the Security System
BIND name server: The releases of host names to IP-addresses are
recorded to these log files.
Admin notifications: The Notification Log Files record all notification e-mails sent by the firewall. This allows an administrator to
monitor critical system messages even if the e-mail system is down.
Error, warning, and information codes are listed in chapter 5.9.3.2 on
page 315.
HTTP proxy: The HTTP proxy logs show the activity of the HTTP
proxy.
Packet Filter: Messages relating to blocked packets are shown in the
Packet Filter logs. These log files are also included in the kernel
logs.
POP3 proxy: The activities of the POP3-Proxy are logged to these log
files. All outgoing e-Mails will be listed there. In addition, all
irregularities, such as interruptions or blocked e-mails will be logged.
Portscan Detection: The Portscan Detection system watches for and
blocks portscans and sends e-mail messages to the administrator.
When examining the Log Files, however, do not draw too many
conclusions from the source IP addresses (SRC) and port numbers
(SPT), as they can easily be falsified by the sender. The destination
addresses (DST) and port numbers (DPT), however, provide useful
information about what the scanner was looking for.
PPPoA DSL dial-up: The processes executed in the dial-up with PPP
over ATM are recorded to these log files.
PPPoA DSL dial-up: The processes executed in the dial-up with PPP
over Ethernet are recorded to these log files.
PPTP VPN Access: These logs record the progress of PPTP sessions
from
external
clients.
This
includes
login
and
authentication
information as well as error messages.
313
Using the Security System
If you select the Extensive parameter in the Logging function of the
Network/PPTP VPN Access menu, these logs will contain very
detailed information about PPP connections.
Self-monitor: The Self-monitoring continually checks the integrity
of the firewall systems and notifies the administrator of important
events. Self-monitoring checks the function, performance and security
of relevant system parameters and remedies deviations, exceeding
given tolerances. Subsequently a report will be sent to the competent
administrator by e-mail.
This Self-monitoring of the security system ensures that central
services such as the Syslog Daemon, HTTP Proxy, and Network
Accounting are functioning properly.
Access rights to files are monitored, as is the resource usage of
individual processes. This is designed to prevent an overload of the
system. Moreover, the system administrator is informed in time on
previsible resource bottlenecks, if, for example the available disk
space is running short. This allows for an early implementation of
measures in favor of a system extension and/or discharge.
SMTP proxy: The activities of the SMTP-proxy are recorded to these
log files. All ingoing e-Mails will be listed there. In addition, all
irregularities, such as assigned Bounce conditions, interruptions or
blocked e-mails will be logged.
SOCKS proxy: The activities of the SOCKS-proxy are recorded to
these log files.
SSH remote login: Information on the log-in processes to the
remote shell is recorded to these log files.
System log messages: These Log Files record generic information
about the daemon processes running on the system. Among other
things, the access to the SNMP-service and the activities of the
Dynamic DNS function, are recorded to these log files.
314
Using the Security System
Up2Date Service messages: The activities of the Up2Date Service
are recorded to these log files. This comprises also the System
Up2Date and Pattern Up2Date processes.
Uplink Failover messages: The activities of the configured failovers
are recorded to these log files.
WebAdmin usage: The use of the WebAdmin configuration tool is
recorded to these log files. The logs contain the configuration
changes, implemented by the configuration tool and also the log-in
and log-out processes.
5.9.3.2.
Error Codes
The following is a list of all error, warning, and information codes with
their meanings:
INFO:
000
System was restarted
System was restarted
010
Backup file
A system backup file was generated automatically
and sent via e-mail to the Administrator.
105
Astaro User Authenticator (AUA) not running –
restarted
106
Cron Task Scheduler not running – restarted
107
WebAdmin webserver not running – restarted
108
ssh server not running – restarted
109
license server not running – restarted
110
configuration
database
server
not
running
–
restarted
111
syslog server not running – restarted
315
Using the Security System
112
middleware not running – restarted
150
Root
partition
mounted
at
/
is
filling
up
-
please check
151
tmpfs partition mounted at /opt/tmpfs is filling
up - please check
152
secure application partition mounted at /var/sec
is filling up - please check
153
logfile partition mounted at /var/log is filling
up - please check
154
storage
application
partition
mounted
at
/var/storage is filling up - please check
155
Up2Date
partition
mounted
at
/var/up2date
is
filling up - please check
300
System Up2Date: System Up2Date started
Further information on the Up2Date Service can
be found in chapters 5.1.3 on page 54.
302
System Up2Date: No new System Up2Date packages
available
303
System Up2Date succeeded: Prefetched new System
Up2Date package(s)
For more Up2Date package information please see
attachted Up2Date description file.
Further information on the System Up2Date can be
found in chapters 5.1.3 on page 54.
320
System Up2Date failed: License is not valid
321
System Up2Date: Started System Up2Date installlation in HA-Master-Mode
322
316
System Up2Date: New System Up2Dates installed
Using the Security System
Further
information
on
the
Up2Date
package(s)
can be found in the notification e-mail.
323
System Up2Date: Started System Up2Date Installation
350
Pattern Up2Date: Started Pattern Up2Date
Further information on the Up2Date Service can
be found in chapters 5.1.3 on page 54.
351
Pattern Up2Date: No new pattern available for
Virus Protection
352
Pattern Up2Date: No new pattern available for
Intrusion Protection
353
Pattern Up2Date: Trying another pattern type
354
Pattern Up2Date succeeded: Updated new Intrusion
Protection patterns
For more information please see the notification
e-mail.
Further
information
on
the
System
Up2Date can be found in chapters 5.1.3 on page
54.
360
Virus Pattern Up2Date: No pattern installation
for Virus pattern needed
361
Virus Pattern Up2Date succeeded: Installed new
Virus Pattern
For more information please see the notification
e-mail.
700
Daily log file archive
This
is
an
archive
file
containing
the
log
files. The date of these log files is specified
in the notification.
710
Log file partition is filling up
317
Using the Security System
The
log
file
partition
usage
reached
the
specified value in percent. Depending on your
configuration the system will automatically take
measures if the usage continues to grow. To make
sure
you
don't
lose
any
important
log
files,
please check the WebAdmin settings and/or remove
old log files manually.
850
Intrusion Protection Event
A packet was identified that may be part of an
intrusion. The matching rule classified this as
low priority level. Further information on the
Intrusion Prevention event can be found in the
notification e-mail.
851
Intrusion
Protection
Event
–
Event
buffering
activated
A packet was identified that may be part of an
intrusion. The matching rule classified this as
low
priority
activated.
will
be
level.
Further
collected
Event
buffering
has
Intrusion
Protection
and
to
sent
you
been
events
when
the
collection period has expired. If more events
occur, this period will be increased. Further
information
on
the
Intrusion
Prevention
event
can be found in the notification e-mail.
855
Portscan detected
A portscan was detected. The originating host
was: <IP>
A portscan from the given IP address was detected.
The
Portscan
Detection
Module
is
scribed in chapter 5.4.1, on page 179.
For more information:
318
see WebAdmin -> Local Logs/Browse/Portscan
de-
Using the Security System
-
search with whois to know who the source
IP belongs to:
-> RIPE NCC http://www.ripe.net/perl/whois?
query=$HOST
-> ARIN - http://www.arin.net/cgi-bin/whois.pl?
queryinput =$HOST
-> APNIC - http://cgi.apnic.net/apnic-bin/
whois.pl?search=$HOST
-
use traceroute from
-> UC Berkeley
-
http://www.net.berkeley.edu/cgi-bin/
traceroute? $HOST
Attention:
source
IP
addresses
can
easily
be
forged by attackers.
856
Portscan detected - Event buffering activated
A portscan was detected. The originating host
was: <IP>
A portscan from the given IP address was detected.
The
Portscan
Detection
Module
is
de-
scribed in chapter 5.4.1, on page 179.
Event
buffering
Intrusion
has
Protection
been
events
activated.
will
be
Further
collected
and sent to you when the collection period has
expired. If more events occur, this period will
be increased. Further information on the Intrusion Prevention event can be found in the notification e-mail.
999
File transfer request
This is the file you requested.
319
Using the Security System
WAR:
001
A feature will expire! The feature ... is time
limited and will expire in ...
Please contact your local Astaro partner or an
Astaro sales representative to obtain a license
update.
E-Mail addresses:
America's: mailto:salesus@astaro.com,
Europe, Asia Pacific and Africa:
mailto:sales@astaro.com.
For
technical
questions,
please
feel
free
to
visit our user bulletin board at
http://www.astaro.org, or our documentation
ressources at http://docs.astaro.org.
005
Failed login attempt from ...(IP) at ...(time)
with ...( username)
080
HA check: no link beat on interface – retrying
The link beat monitoring system on the firewall
failed. The system will now try again. If the
system continues to fail, the administrator will
receive message WAR 081.
If
you
do
not
wish
to
use
this
monitoring
function, no further action is required. After
the system sends the WAR 081 message, it will
not try to start the link beat monitoring system
again.
081
HA check: interface does not support link beat
check
The
link
multiple
beat
monitoring
attempts.
If
you
system
have
failed
after
recently
in-
stalled the HA system, and you intend to use the
320
Using the Security System
link beat monitoring system, please check that
the network cards support link beat, and that
they are supported by the security system. Also
check to make sure that the link beat capable
cards
have
been
chosen
for
the
data
transfer
connection.
The installation and management of the HA system
is described in chapter 5.1.10, on page 97.
711
Log file(s) have been deleted
The
log
file
partition
usage
reached
the
specified value in percent. Log Files have been
deleted. To make sure you don't lose more log
file(s),
and/or
please
remove
check
old
the
log
WebAdmin
files
settings
manually.
The
deleted files and/or directories are listed in
the attachment.
715
Remote log file storage failed
The daily log file archive could not be stored
on the configured remote server. Please check
the WebAdmin settings for:
Local Logs/Settings/Remote log file archive
The
archive
file
will
be
automatically
re-
transfered with the next daily log file archive.
850
Intrusion Protection Event
A packet was identified that may be part of an
intrusion. The matching rule classified this as
medium
priority
level.
Further
information
on
the Intrusion Prevention event can be found in
the notification e-mail.
851
Intrusion
Protection
Event
–
Event
buffering
activated
321
Using the Security System
A packet was identified that may be part of an
intrusion. The matching rule classified this as
medium priority level. Event buffering has been
activated.
will
be
Further
collected
Intrusion
Protection
and
to
sent
you
events
when
the
collection period has expired. If more events
occur, this period will be increased. Further
information
on
the
Intrusion
Prevention
event
can be found in the notification e-mail.
CRIT:
301
System
Up2Date
failed:
Could
not
connect
to
Authentication Server(s)
The authentication server is not reachable. If
the problem continues, please contact the support department of your firewall provider.
302
System
Up2Date
failed:
Download
of
System
Up2Date Packages failed
If
the
problem
continues,
please
contact
the
support department of your firewall provider.
305
System Up2Date: Wrong MD5sum for local System
Up2Date package
Please
download
a
new
Up2Date
package.
The
Up2Date packages can be downloaded from http://
download.astaro.de/asl/up2date.
If
the
problem
recurs, please contact the support department of
your firewall provider.
306
System Up2Date failed: Wrong MD5sum for downloaded Up2Date Package
Please download a new Up2Date package. If the
problem
recurs,
please
contact
the
department of your firewall provider.
322
support
Using the Security System
320
System Up2Date failed: Wrong start parameters
If the problem recurs, please contact the support department of your firewall provider.
322
System
Up2date
stopped:
Next
Up2Date
install-
lation locked by HA
323
System Up2Date failed: Corrupt Up2Date Package
Found corrupt Up2Date package. Please start process again. If the problem recurs, please contact
the
support
department
of
your
firewall
provider.
324
System Up2Date failed: Invalid License
Your license is no longer valid.
325
System Up2Date failed: License check failed
Your
license
problem
could
continues,
not
please
be
checked.
contact
the
If
the
support
department of your firewall provider.
333
System Up2Date failed: Internal error
The
system
update
failed.
Please
contact
the
support department of your firewall provider.
334
System Up2Date failed: Invalid syntax
The
system
update
failed.
Please
contact
the
support department of your firewall provider.
335
System Up2Date failed: Could not read Up2Date
directory
The
system
update
failed.
Please
contact
the
support department of your firewall provider.
336
System Up2Date failed: No installation directory
The
system
update
failed.
Please
contact
the
support department of your firewall provider.
323
Using the Security System
337
System Up2Date failed: Could not extract tar
Please
start
process
again.
If
the
problem
recurs, please contact the support department of
your firewall provider.
338
System Up2Date failed: Main Up2Date package not
found
Please
start
process
again.
If
the
problem
recurs, please contact the support department of
your firewall provider.
339
System Up2Date failed: Version conflict
The
system
update
failed.
Please
contact
the
support department of your firewall provider.
340
System Up2Date failed: Pre-Stop-Services script
failed
341
System Up2Date failed: Post-Stop-Services script
failed
342
System Up2Date failed: Pre-Start-Services script
failed
343
System Up2Date failed: Starting Services failed
The
system
update
failed.
Please
contact
the
support department of your firewall provider.
344
System
Up2Date
failed:
Post-Start-Services
script failed
345
System
Up2Date
failed:
Error
occured
while
running installer
The
system
update
failed.
Please
contact
the
support department of your firewall provider.
346
System Up2Date failed: Installer ended due to
internal error
324
Using the Security System
The
system
update
failed.
Please
contact
the
support department of your firewall provider.
347
System
Up2Date
failed:
Started
without
rpm
parameters
The
system
update
failed.
Please
contact
the
support department of your firewall provider.
351
Pattern
Up2Date
failed:
Could
not
select
please
contact
Authentication Server(s)
If
the
problem
continues,
the
support department of your firewall provider.
352
Pattern
Up2Date
failed:
Could
not
connect
to
Authentication Server(s)
The authentication server is not reachable. If
the problem continues, please contact the support department of your firewall provider.
353
Virus Pattern Up2Date failed: Could not connect
to Up2Date Server
The
Up2Date
problem
server
continues,
is
not
please
reachable.
contact
If
the
the
support
Up2Date
failed:
department of your firewall provider.
354
Intrusion
Protection
Pattern
Could not connect to Up2Date Server
The
Up2Date
problem
server
continues,
is
not
please
reachable.
contact
the
If
the
support
department of your firewall provider.
355
Virus Pattern Up2Date failed: No active bases
for Virus Patterns found
356
Intrusion Protection Pattern Up2Date failed: No
active bases for Intrusion Protection Patterns
found
325
Using the Security System
357
Virus
Pattern
Up2Date
failed:
Internal
MD5Sum
Error
Could not create correct MD5Sums. If the problem
recurs, please contact the support department of
your firewall provider.
358
Intrusion
Protection
Pattern
Up2Date
failed:
Internal MD5Sum Error
Could not create correct MD5Sums. If the problem
recurs, please contact the support department of
your firewall provider.
360
Pattern Up2Date failed: Licence Check failed
Your
license
problem
could
continues,
not
be
please
checked.
contact
the
If
the
support
department of your firewall provider.
361
Pattern Up2Date failed: Restart of Virus Scanner
failed
If
the
problem
continues,
please
contact
the
support department of your firewall provider.
362
Pattern Up2Date failed: MD5Sum Error occurred
If
the
problem
continues,
please
contact
the
support department of your firewall provider.
712
System shut down due to full log file partition
The
log
file
partition
usage
reached
the
specified value in percent. To prevent the loss
of important log files, the system has been shut
down
automatically.
Please
check
the
WebAdmin
settings and/or remove old log files.
850
Intrusion Protection Event
A packet was identified that may be part of an
intrusion. The matching rule classified this as
326
Using the Security System
highest priority level. Further information on
the Intrusion Prevention event can be found in
the notification e-mail.
851
Intrusion
Protection
Event
–
Event
buffering
activated
A packet was identified that may be part of an
intrusion. The matching rule classified this as
highest priority level. Event buffering has been
activated.
will
be
Further
collected
Intrusion
Protection
and
to
sent
you
events
when
the
collection period has expired. If more events
occur, this period will be increased. Further
information
on
the
Intrusion
Prevention
event
can be found in the notification e-mail.
860
Intrusion Protection Event - Buffered Events
After
the
activation
of
the
event
buffering
further IPS events have been collected. Please
see the attached file for a list of collected
events. This list will show you a maximum of
events. A complete event history has been stored
in the Intrusion Protection log files.
327
Using the Security System
5.10. Online Help
The Help menu contains further functions for use with the Online
Help system.
Search
This function allows you to search WebAdmin’s Online Help system
for a particular term. Results will appear in a separate window.
Starting a search:
1.
Under the Online Help tab, open the Search menu.
2.
Enter your search term in the Search term field.
3.
Begin the search by clicking seek.
If the term is found in either WebAdmin or the Online Help system,
the following results will be returned:
•
path to the relevant function in WebAdmin
•
link to the relevant Online Help page
•
Information on the function or texts of the Online help with the
expression, searched for
Glossary
The glossary explains the concepts and terms used in WebAdmin.
Click a term to see a short explanation.
328
Using the Security System
5.11. Exiting the Security Solution
If you close a browser running a WebAdmin session without using
the Exit function, the session will remain active until the timeout is
reached.
In such a case you can again log in to WebAdmin. A screen will be
displayed, informing you that already another user is logged in. To log
in again, first end the other session by clicking the Kick button. If you
wish to end another administrator’s active session, you can type a
message in the “Type reason here” field which will be transmitted to
the other administrator.
329
Glossary
Glossary
Broadcast
The address used by a computer to send a message to all other
computers on the network at the same time.
Example:
A
network
with
address
212.6.145.0
and
netmask
255.255.255.240 would have a broadcast address of 212.6.145.15.
Client
A client is a program that communicates over a network with a server
in order to make use of a particular service.
Example: Netscape is a WWW client, and communicates with a WWW
server to download web pages.
Client-Server model
Applications based on the client-server model use a client program on
the user’s computer to communicate with a central server program on
the network. The server is usually responsible for keeping track of the
data, while the client is responsible for presenting the data to the
user. In order to function correctly, the client and server must both
use a well-defined network protocol to communicate. All important
applications on the Internet (e.g. WWW, FTP, news) use this model.
DNS
The Domain Name Systems (also: The Domain Name Service)
translates
the
underlying
IP
addresses
of
Internet-connected
computers into more human-friendly names or aliases and vice-versa.
This translation from number to name is done by the name server.
Every Internet-connected institution must employ at least two
separate DNS servers to answer queries about its internal DNS names
330
Glossary
and IP numbers. Every top-level domain also has name servers which
contain information about their subordinate servers.
The DNS system is thus a distributed, hierarchical database. DNS
resolution is normally handled by network applications rather than by
the user him or herself.
Dual-Homed Gateway
A dual-homed gateway is a computer that is directly connected to two
networks (i.e., it has two network cards, each connected to a different
network) and which forwards information from one network to the
other. Due to the fact that there is no IP forwarding, all connections
must be forwarded through this Dual-Homed Gateway.
Firewall
A firewall protects one network or subnet (e.g., an internal LAN) from
another network (e.g., the public Internet). All traffic between the two
passes through the firewall, where it is controlled and monitored.
Header
In general, the header is the information contained at the top of a file
or message, and consists of low-level data regarding the status and
handling of the file or message. In particular, the header of an e-mail
or Usenet message contains information such as the sender, recipient,
and date.
Host
In a client-server architecture, the host is the computer which runs
the server software. One host can have multiple server programs
running on it: that is, an FTP server, mail server, and web server can
all run on the same host. A user uses a client program, for instance a
browser, to access the server on the host. The word Server is also
331
Glossary
often used to refer to the computer on which the server software
runs, diluting the distinction between server and host in practice.
In telecommunications, the host is the computer from
which
information (such as FTP files, news, or WWW pages) is retrieved. On
the Internet, hosts are often also called nodes.
Using an Internet host (as opposed to a Localhost), for example with
Telnet, one can work from a distance (Remote Access).
ICMP
Next to the IP Protocol, there is an option with specific functions.
The Internet Control Message Protocol (ICMP) is a special kind of
IP protocol used to send and receive information about the
network’s status and other control information. Many users are
already familiar with ICMP echo requests (type 8) and echo replies
(type 0), as these are used by the ping program. When a computer
receives an echo request, its IP stack sends back an echo reply: This
is done with the ping program in order to determine, whether another
network component is reachable.
IP
The Internet Protocol is the basic protocol of the Internet, and has
been used without change since it was first developed in 1974. It
handles the basic transmission of data from one computer to another,
and serves as the basis for higher-level protocols like TCP and UDP. It
handles the connection and error management. Technologies like NAT
and Masquerading allow large private networks to hide behind small
numbers of IP addresses (or even single addresses), thus allowing the
relatively limited IPv4 address space to meet the demands of an everexpanding Internet.
332
Glossary
IP-Address
Every (publicly-addressable) host on the Internet has a unique IP
address, similar to a telephone number. An IP address consists of
decimal numbers, separated by points. Possible numbers are 0 to 255
inclusive.
Example: a possible IP address is 212.6.145.1.
At least one IP name in the form hostname[[.subdomain]s].domain,
z. B. kises.rz.uni-konstanz.de is assigned to an IP address. This
refers to a computer, named kises, which stands in the sub-domain
rz of the sub-domain uni-konstanz of the de domain. As with IP
addresses, the individual parts of the name are separated from each
other by a point. Whereas, in contrast to IP-addresses, IP-names are
not limited to four numbers. Moreover, several IP-names can be
assigned to one IP-address, which are referred to as aliases.
Masquerading
Dynamic Masquerading is a technology based on NAT that allows an
entire LAN to use one public IP address to communicate with the rest
of the Internet.
Example: The administrator has established an internal LAN, and has
given each computer on it IP addresses from the private IP range
10.x.x.x. One computer, for example, has the address 10.1.2.3. Only
one, official IP address is assigned to all computers in its network, i.e.
if only one HTTP request starts to the Internet, its IP address will be
replaced by the IP address of the external network card.
The data traffic for the external network (Internet) thus does not
contain internal information. The answer to the request will be
recognized by the firewall and forwarded to the requesting computer.
333
Glossary
nslookup
Nslookup is originally a UNIX program designed to query name
servers. The main application is the display of IP names in the case of
a given IP number and vice versa. Moreover also additional functions,
such as aliases can be displayed.
Port
While at the IP level, only sender and destination addresses are
important, the TCP and UDP protocols both include the concept of
ports. A port is an additional identifier – in the cases of TCP and UDP,
a number between 0 and 65535 – that allows a computer to
distinguish between multiple concurrent connections between the
same two computers. TCP and UDP packets have both a sending port
and a destination port.
Protocol
A protocol is a well-defined and standardized set of rules that govern
how a client and server interact. Some well-known protocols and their
associated services include HTTP (WWW), FTP (FTP), and NNTP
(news).
Proxy (Application Gateway)
Proxies, often called application gateways, separate two networks at
the network (IP or TCP/UDP) level, while still allowing certain kinds of
communication. There can be no direct connection between an
internal system and an external computer.
Proxies exclusively operation the application level. Proxies-based
firewalls use a Dual-Homed Gateway that does not forward IP
packets. Proxies, operated as specialized programs on the gateway,
can now receive connections for a specific protocol, treat the
transmitted traffic on the application level and forward it afterwards.
334
Glossary
RADIUS
RADIUS stands for Remote Authentication Dial In User Service. It is a
protocol designed to allow network devices such as routers to
authenticate users against a central database.
Router (Gateway)
A router is a network device that is designed to forward packets to
their destination along the most efficient path. Strictly speaking, a
gateway is not always a router (it could be an application gateway, or
proxy) – though a router is a kind of circuit-level gateway. When a
computer wants to communicate with a server not on the local
network, it must pass the data to a router in order for the packets to
be forwarded to their destination: By convention, the highest or
lowest address in the network range is used for the router: for
example, in the network 192.168.179.0/24, the router will normally
be at either 192.168.179.254 or 192.168.179.1.
Server
A server is a network-connected computer that offers services to
client computers. Standard services include WWW, FTP, news, and so
on. In order to make use of these services, the user will need a client
program (e.g., Netscape) to communicate with the server.
SOCKS
SOCKS is a proxy protocol that allows a point-to-point connection
between an internal and an external computer. SOCKS, often called
the Firewall Traversal Protocol, is currently at version 5 and must be
implemented in the client-side program in order to function correctly.
335
Glossary
Subnet Mask
The subnet mask (also called netmask) of a network, together with
the network address, defines which addresses are part of the local
network and which are not. Individual computers will be assigned to a
network on the basis of the definition.
UNC-Path
The Universal Naming Convention path is used primarily by
computers
running
a
Microsoft
operating
system
to
uniquely
designate network resources. UNC paths are usually of the form
\\Server\Resource.
336
Index
Index
Accounting
adding/deleting a network
card ........................ 176
Accounting...................... 175
Acoustic signals
Beep, 5 times ............. 102
Administrator e-mail addresses
..................................44
Backup
editing E-Mail Addresses .68
E-Mail Backup File encrypt
................................66
E-Mail Backup File generate
................................67
introduction ..................62
load.............................63
manual creation ............64
Broadcast
Internet-wide.............. 198
segment-wide ............. 199
Certificate for WebAdmin
installing ......................95
Certificate for WebAdmin
creating .......................95
Certificate, WebAdmin Site ..94
Connection Tracking Helpers
Intro.......................... 203
Loading Helper Modules 204
Connection Tracking Table. 206
Current System NAT Rules 206
Current System Packet Filter
Rules ......................... 206
DHCP Server
assigning DNS Servers . 166
configuring ................. 165
Current IP leasing table 168
introduction ................ 165
DHCP Server
Static mappings .......... 167
DNS Proxy
configuring ................. 226
DNS Server
deleting...................... 109
editing ....................... 109
DNS servers
adding ....................... 106
Dynamic DNS
Host defining .............. 119
Dynamic DNS .................. 118
Errors
Causes.........................26
Errors
Causes....................... 123
Exit................................ 329
Factory Reset ....................50
Firewall Hostname ........... 118
General System Settings.....44
Glossary
Broadcast ................... 330
Client......................... 330
Client-Server model ..... 330
DNS .......................... 330
Dual-Homed Gateway .. 331
Firewall ...................... 331
Header....................... 331
Host .......................... 331
ICMP ......................... 332
IP.............................. 332
IP-Address.................. 333
Masquerading ............. 333
nslookup .................... 334
Port ........................... 334
Protocol ..................... 334
Proxy......................... 334
RADIUS...................... 335
Router ....................... 335
Server ....................... 335
SOCKS....................... 335
Subnet Mask ............... 336
UNC-Path ................... 336
337
Index
Glossary ......................... 328
Group
deleting...................... 109
editing ....................... 109
Header ........................... 250
High Availability.................97
High Availability System
installing ......................98
Host
adding ....................... 104
deleting...................... 109
editing ....................... 109
Hostname ....................... 118
HTTP
Surf Protection categories
.............................. 214
HTTP Proxy
enabling the HTTP proxy
.............................. 211
Operation modes ......... 210
User Authentication Mode
.............................. 211
HTTP-Proxy
Advanced ................... 224
Global Settings............ 210
Standard Mode............ 210
Transparent Mode........ 210
ICMP
Firewall forwards ping .. 203
Firewall forwards
Traceroute................ 202
Firewall is ping visible .. 203
Firewall is Traceroute
visible...................... 202
ICMP Forwarding ......... 200
ICMP on firewall .......... 201
introduction ................ 200
Log ICMP Redirects ...... 201
Ping on firewall ........... 203
Ping Settings .............. 203
Traceroute from Firewall
.............................. 202
Traceroute Settings ..... 201
338
Ident
Forward Connections.... 234
Introduction................ 234
Installation
Configuration ................27
Instructions ..................22
Preparation...................22
Software ......................22
Interfaces
adding additional addresses
.............................. 128
Additional address on
Ethernet interface...... 128
Configuring a Virtual LAN
.............................. 142
Configuring PPPoA-DSL. 151
Configuring PPPoE-DSL. 146
Current status............. 121
Downlink Bandwidth (kbits)
.........127, 144, 148, 154
Ethernet network card.. 124
introduction ................ 119
introduction ................ 119
MTU Size .....127, 144, 148,
154
PPPoE-DSL Connection . 145
PPPoE-DSL Connections 150
Proxy ARP .................. 125
QoS Status ..126, 143, 147,
153
Standard Ethernet Interface
.............................. 124
Uplink Bandwidth (kbits)
.........126, 144, 148, 154
Uplink Failover on Interface
.............................. 125
Virtual LAN ................. 140
Wireless LAN............... 130
Wireless LAN Security .. 130
Interfaces
determining MAC Addresses
.............................. 133
Hardware overview ...... 122
Index
Wireless LAN Access Point
.............................. 134
Wireless LAN Station .... 137
Intrusion Protection
Global Settings............ 179
introduction ................ 179
Portscan Detection....... 179
IPS rule
setting ....................... 184
IPSec user group
defining...................... 107
IPSec VPN
AH-Protocol ................ 262
CA Management .......... 285
Connections................ 265
Global IPSec Settings ... 265
introduction ................ 256
IPSec......................... 260
IPSec Connections ....... 266
IPSec Modes ............... 261
IPSec System Information
.............................. 266
IPSec-Protocols ........... 262
Key management ........ 263
L2TP over IPSec .......... 283
Local IPSec X.509 Key.. 277
Local Keys .................. 277
Manual Key Distribution 263
Policies ...................... 273
PSK Authentication ...... 279
Remote Keys .............. 280
RSA Authentication ...... 278
Transport Mode ........... 261
Tunnel Mode ............... 261
VPN Routes................. 266
VPN Status ................. 266
IPSec VPN
configuring ................. 267
Configuring a Policy ..... 274
Defining Remote Keys .. 280
Generate a Client/Host
Certificate ................ 287
L2TP over IPSec
L2TP over IPSec Client
Parameters............... 284
L2TP over IPSec IP Pool 284
L2TP over IPSec Settings
.............................. 283
Licensed Users ..................53
Licensing ..........................50
Licensing Information .........53
Load Balancing
deleting rules .............. 164
editing rules ............... 164
Load Balancing ................ 163
Load Balancing
defining rules .............. 163
Local Logs
Browse ...................... 307
filtering ...................... 310
Filters ........................ 310
Introduction................ 302
Local Log File Archive ... 303
Local Log File Level define
.............................. 303
Local Log File Query..... 306
Log Files..................... 311
Remote Log File Archive 304
Search start................ 306
Settings ..................... 302
Local User
deleting...................... 117
editing ....................... 117
Local User
adding ....................... 115
Log files
error codes ................. 315
Log Files
Admin notifications ...... 313
Astaro Configuration
Manager................... 311
Astaro User Authentication
.............................. 311
BIND name server ....... 313
Boot messages............ 311
Configuration daemon .. 311
339
Index
Content Filter.............. 311
DHCP client ................ 311
DHCP server ............... 311
Fallback archive .......... 311
High Availability .......... 312
HTTP daemon ............. 312
HTTP proxy................. 313
Intrusion Protection ..... 312
IPSec VPN .................. 312
Kernel........................ 312
Local Login ................. 312
Logging...................... 312
MiddleWare................. 312
Network accounting
deamon ................... 312
Packet Filter................ 313
POP3 proxy................. 313
Portscan Detection....... 313
PPPoE DSL dial-up ....... 313
PPTP VPN Access ......... 313
Selfmonitor................. 314
SMTP proxy ................ 314
SOCKS proxy .............. 314
SSH remote login ........ 314
System log messages... 314
Up2Date Service messages
.............................. 315
Uplink Failover messages
.............................. 315
Virus Protection........... 312
WebAdmin access ........ 312
WebAdmin usage......... 315
Log Files Settings
Level defining ............. 304
Masquerading
deleting rules .............. 162
editing rules ............... 162
Masquerading.................. 161
Masquerading
defining rules .............. 162
Microsoft Outlook
Creating rules ............. 245
MS Explorer
340
Disabling Proxy Use ..... 209
NAT
Defining rules ............. 159
deleting rules .............. 161
editing rules ............... 161
introduction ................ 157
Network
adding ....................... 105
deleting...................... 109
editing ....................... 109
filtering ...................... 108
Introduction................ 103
Network group
defining...................... 106
Networks
Filters ........................ 108
Networks ........................ 103
Notification ..................... 118
Packet Filter
Advanced ................... 203
System Information ..... 205
Packet Filter Live Log........ 205
Packet filter rule
adding/editing groups .. 194
enable, disable ............ 194
sorting rules table........ 194
Packet filter rules
rules table .................. 193
Packet Filter Rules
deleting...................... 194
editing ....................... 194
filtering ...................... 195
Filters ........................ 195
introduction ................ 188
re-ordering ................. 194
Packet Filter Rules
setting ....................... 190
Pattern Up2Date
installation, automatic ....60
installation, manual .......60
Ping
Using ......................... 178
Ping Check...................... 177
Index
POP3
Content Filter.............. 230
Header....................... 232
Spam Protection .......... 230
Virus Protection........... 230
POP3
configuring ................. 229
PPTP VPN
introduction ................ 169
MS Windows 2000 Scenario
.............................. 171
PPTP Client Parameters 171
PPTP IP-pool ............... 170
PPTP VPN Access ......... 169
Protocols
AH...................... 110, 112
ESP .................... 110, 112
IP.............................. 112
TCP ........................... 110
UDP........................... 110
Proxy
DNS .......................... 225
HTTP ......................... 208
Ident ......................... 234
Introduction................ 207
POP3 ......................... 229
Proxy Content Manager 251
SMTP ......................... 235
SOCKS....................... 227
Proxy Content Manager
Age ........................... 252
deferred/zurückgestellt. 252
filtern ........................ 254
Filters ........................ 254
Global Actions ............. 254
Mail-ID....................... 252
permanent
error/andauernder Fehler
.............................. 253
quarantined/gesperrt ... 252
Recipient(s) ................ 253
Sender....................... 253
smtp_queue ............... 252
Proxy disable
Netscape .................... 208
Quality of Service (QoS) ... 196
Reporting
Accounting ................. 298
Administration............. 293
Content Filter.............. 296
Current Report ............ 298
Daily Executive Report by
E-Mail ...................... 297
DNS .......................... 297
Executive Report ......... 297
Hardware ................... 294
HTTP Proxy Usage ....... 297
Intrusion Protection ..... 297
Network ..................... 295
Packet Filter................ 296
PPTP/IPSec VPN .......... 297
System Information ..... 300
Virus.......................... 294
Reporting
Accounting
configuring ................ 299
Restart ........................... 102
Routing
Introduction................ 155
Kernel Routing Table .... 156
Search ........................... 328
Search
starting a search ......... 328
Secure Shell................ 48, 49
Service
adding ....................... 111
deleting...................... 114
editing ....................... 114
filtering ...................... 113
introduction ................ 110
Service group
defining...................... 112
Services
Filters ........................ 113
Services ......................... 110
Settings............................44
341
Index
Shut down ...................... 102
Shut down/Restart ........... 102
SMTP
Block RCPT Hacks ........ 240
configure.................... 236
DoS Protection ............ 236
Encryption/Authentication
.............................. 238
Expression Filter.......... 244
File Extension Filter...... 242
Global Whitelist ........... 239
introduction ................ 235
MIME Error Checking.... 241
Postmaster address ..... 236
Realtime Blackhole Lists 247
Sender Address Verification
.............................. 247
Sender Blacklist........... 240
Spam Protection ... 247, 248
Virus Protection ........... 243
Virus Protection/Content
Filter ....................... 240
SMTP Relay
Virus Protection........... 243
SNMP Access
Zugang erlauben ...........69
SOCKS Proxy
configuring ................. 228
SOCKS Proxy
User Authentication ..... 228
Static Routing
Intro.......................... 155
Static Routing
defining routes ............ 156
Surf Protection
Categories .................. 217
Content Removal ......... 218
editing Surf Protection
categories ................ 214
enabling, Profiles adding
.............................. 219
introduction ................ 213
342
Profile Assignment Table
.............................. 221
Profile Functions ... 216, 222
Profiles assign ............. 223
Profiles editing ............ 219
Profiles Table .............. 215
URL Blacklist............... 217
URL Whitelist .............. 216
SYN Rate Limiter
Einführung.................. 204
System Requirements
Administration PC ..........20
Example Configuration ...20
Hardware .....................19
System Time
automatic synchronization
................................47
manual configuration .....46
System Up2Date
installing ......................58
installing with HA solution
................................58
loading and installation,
manual ......................56
loading, local ................57
System Up2Date
loading, automatic ........56
Time Settings ....................45
Up2Date Service
Introduction..................54
Pattern Up2Date............59
System Up2Date ...........55
Use external indicators .......44
User
filtering ...................... 116
User Authentication
configuring LDAP ...........87
configuring MS Active
Directory Server..........80
configuring Novell
eDirectory Server ........85
Einführung....................71
LDAP advanced .............90
Index
LDAP Server .................78
Microsoft IAS RADIUS
configuration ..............73
RADIUS........................72
SAM ............................76
SAM – NT/2000/XP
configuration ..............76
User Authentication
configuring OpenLDAPServer .......................86
Users
Filters ........................ 116
introduction ................ 114
Users ............................. 114
WebAdmin
blocking protection for
Loggin attempts ..........93
Drop-down Menus..........38
HTTPS..........................91
Info Box .......................35
Kick.............................43
Lists ............................39
Menus..........................36
Online help ...................40
Refresh ........................41
Selection Fields .............36
starting ........................43
Status Light ..................36
Tab list ........................35
343
© Astaro AG
www.astaro.com