Lab B: Configuring a Remote Access VPN Server and Client

Chapter 8: Lab B: Configuring a Remote Access VPN Server and
Client
Topology
IP Addressing Table
Interface
FA0/1
IP Address
192.168.1.1
Subnet Mask
255.255.255.0
Default Gateway
N/A
Switch Port
S1 FA0/5
S0/0/0 (DCE)
10.1.1.1
255.255.255.252
N/A
N/A
S0/0/0
10.1.1.2
255.255.255.252
N/A
N/A
S0/0/1 (DCE)
10.2.2.2
255.255.255.252
N/A
N/A
FA0/1
192.168.3.1
255.255.255.0
N/A
S3 FA0/5
S0/0/1
10.2.2.1
255.255.255.252
N/A
N/A
PC-A
NIC
192.168.1.3
255.255.255.0
192.168.1.1
S1 FA0/6
PC-C
NIC
192.168.3.3
255.255.255.0
192.168.3.1
S3 FA0/18
Device
R1
R2
R3
206
Objectives
Part 1: Basic Router Configuration
•
Configure host names, interface IP addresses, and access passwords.
• Configure static routing.
Part 2: Configuring a Remote Access VPN
•
Configure a zone-based firewall (ZBF) on R3 using SDM.
•
Configure Router R3 to support Cisco Easy VPN Server using SDM.
•
Configure the Cisco VPN Client on PC-A and connect to R3.
•
Verify the configuration.
•
Test VPN functionality.
Background
VPNs can provide a secure method of transmitting data over a public network, such as the Internet. A
common VPN implementation is used for remote access to a corporate office from a telecommuter location
such as a small office or home office (SOHO).
In this lab, you build a multi-router network and configure the routers and hosts. You configure a remote
access IPsec VPN between a client computer and a simulated corporate network. You start by using SDM to
configure a zoned-based firewall (ZBF) to prevent connections from outside the corporate network. You also
use SDM to configure Cisco Easy VPN Server on the corporate gateway router. Next, you configure the Cisco
VPN Client on a host and connect to the corporate network through a simulated ISP router.
The Cisco VPN Client allows organizations to establish end-to-end, encrypted (IPsec) VPN tunnels for secure
connectivity for mobile employees or teleworkers. It supports Cisco Easy VPN, which allows the client to
receive security policies upon a VPN tunnel connection from the central site VPN device (Cisco Easy VPN
Server), minimizing configuration requirements at the remote location. Easy VPN is a scalable solution for
remote access deployments for which it is impractical to individually configure policies for multiple remote
PCs.
Router R1 represents a remote site, and R3 represents the corporate headquarters. Host PC-A simulates an
employee connecting from home or a small office over the Internet. Router R2 simulates an Internet ISP
router and acts as a passthrough with no knowledge of the VPN connection running through it.
Note: The router commands and output in this lab are from a Cisco 1841 with Cisco IOS Release 12.4(20)T
(Advanced IP image). Other routers and Cisco IOS versions can be used. See the Router Interface Summary
table at the end of the lab to determine which interface identifiers to use based on the equipment in the lab.
Depending on the router model and Cisco IOS version, the commands available and output produced might
vary from what is shown in this lab.
Note: Make sure that the routers and the switches have been erased and have no startup configurations.
Required Resources
•
3 routers with Cisco 1841 with Cisco IOS Release 12.4(20)T1 or comparable (2 routers with SDM 2.5
installed)
•
2 switches (Cisco 2960 or comparable)
207
•
PC-A - Windows XP or Vista (with Cisco VPN Client)
•
PC-C (Windows XP or Vista)
•
Serial and Ethernet cables as shown in the topology
•
Rollover cables to configure the routers via the console
Part 1. Basic Router Configuration
In Part 1, you set up the network topology and configure basic settings, such as the interface IP addresses
and static routing. Perform the steps on the routers as indicated.
Step 1: Cable the network as shown in the topology.
Attach the devices shown in the topology diagram, and cable as necessary.
Step 2: Configure basic settings for all routers.
a. Configure host names as shown in the topology.
b. Configure the physical interface IP addresses as shown in the IP addressing table.
c. Configure a clock rate for the routers with a DCE serial cable attached to their serial interface.
R1(config)#interface S0/0/0
R1(config-if)#clock rate 64000
d. Disable DNS lookup to prevent the router from attempting to translate incorrectly entered commands
as though they were host names.
R1(config)#no ip domain-lookup
Step 3: Configure static default routes on R1 and R3.
Configure a static default route from R1 to R2 and from R3 to R2.
R1(config)#ip route 0.0.0.0 0.0.0.0 10.1.1.2
R3(config)#ip route 0.0.0.0 0.0.0.0 10.2.2.2
Step 4: Configure static routes on R2.
Configure a static route from R2 to the R1 LAN.
R2(config)#ip route 192.168.1.0 255.255.255.0 10.1.1.1
Configure a static route from R2 to the R3 LAN.
R2(config)#ip route 192.168.3.0 255.255.255.0 10.2.2.1
Step 5: Configure PC host IP settings.
Configure a static IP address, subnet mask, and default gateway for PC-A and PC-C, as shown in the IP
addressing table.
208
Step 6: Verify connectivity between PC-A and R3.
From PC-A, ping the R3 S0/0/1 interface at IP address 10.2.2.1.
PC-A:\>ping 10.2.2.1
Are the results successful? _____
If the pings are not successful, troubleshoot the basic device configurations before continuing.
Step 7: Configure a minimum password length.
Note: Passwords in this lab are set to a minimum of 10 characters, but are relatively simple for the benefit
of performing the lab. More complex passwords are recommended in a production network.
Use the security passwords command to set a minimum password length of 10 characters.
R1(config)#security passwords min-length 10
Step 8: Configure the enable secret password and console and vty lines.
a. Configure the enable secret password cisco12345 on R1.
R1(config)#enable secret cisco12345
b. Configure a console password and enable login for router R1. For additional security, the exectimeout command causes the line to log out after 5 minutes of inactivity. The logging synchronous
command prevents console messages from interrupting command entry.
Note: To avoid repetitive logins during this lab, the exec-timeout can be set to 0 0, which prevents
it from expiring. However, this is not considered a good security practice.
R1(config)#line console 0
R1(config-line)#password ciscoconpass
R1(config-line)#exec-timeout 5 0
R1(config-line)#login
R1(config-line)#logging synchronous
c. Configure the password on the vty lines for router R1.
R1(config)#line vty 0 4
R1(config-line)#password ciscovtypass
R1(config-line)#exec-timeout 5 0
R1(config-line)#login
d. Repeat these configurations on R2 and R3.
Step 9: Encrypt clear text passwords.
a. Use the service password-encryption command to encrypt the console, aux, and vty passwords.
R1(config)#service password-encryption
b. Issue the show run command. Can you read the console, aux, and vty passwords? Why or why not?
___________________________________________
c. Repeat this configuration on R2 and R3.
209
Step 10: Configure a login warning banner on routers R1 and R3.
Configure a warning to unauthorized users with a message-of-the-day (MOTD) banner.
R1(config)#banner motd $Unauthorized access strictly prohibited and
prosecuted to the full extent of the law$
Step 11: Save the basic running configuration for all three routers.
Save the running configuration to the startup configuration from the privileged EXEC prompt.
R1#copy running-config startup-config
Part 2. Configuring a Remote Access VPN
In Part 2 of this lab, you configure a firewall and a remote access IPsec VPN. R3 is configured as a VPN
server using SDM, and PC-A is configured as a Cisco VPN Client.
Task 1. Prepare R3 for SDM Access
Step 1: Configure HTTP router access and a AAA user prior to starting SDM.
a. Enable the HTTP server on R3.
R3(config)#ip http server
Note: For added security, you can enable the HTTP secure server on R3 using the ip http secureserver command. The HTTP server and the HTTP secure server are disabled by default.
b. Create an admin01 account on R3 with privilege level 15 and a password of admin01pass for use with
AAA.
R3(config)#username admin01 privilege 15 password 0 admin01pass
Step 2: Access SDM and set command delivery preferences.
a. Run the SDM application or open a browser on PC-C. Start SDM by entering the R3 Fa0/1 IP address
192.168.3.1 in the address field.
b. Log in with no username and the enable secret password cisco12345.
c. In the Authentication Required dialog box, enter cisco12345 in the Password field and click OK.
d. If the IOS IPS Login dialog box appears, enter the enable secret password cisco12345.
e. Select Edit > Preferences to allow you to preview the commands before sending them to the router. In the
User Preferences window, check the Preview commands before delivering to router check box and click
OK.
Task 2. Configure a ZBF Firewall on R3
Step 1: Use the SDM Firewall Wizard to configure a zone-based firewall (ZBF) on R3.
a. Click the Configure button at the top of the SDM screen, and then click Firewall and ACL.
210
b. Select Basic Firewall and click the Launch the selected task button. On the Basic Firewall
Configuration wizard screen, click Next.
c. Check the Inside (trusted) check box for FastEthernet0/1 and the Outside (untrusted) check box for
Serial0/0/1. Click Next. Click OK when the SDM launch warning for Serial0/0/1 is displayed.
211
d. In the next window, select Low Security for the security level and click Next.
e. In the Summary window, click Finish.
f. Click Deliver to send the commands to the router. Click OK in the Commands Delivery Status window.
Click OK on the Information window. You are returned to the Edit Firewall Policy tab as follows.
Step 2: Verify firewall functionality.
a. From PC-C, ping the R2 interface S0/0/1 at IP address 10.2.2.2.
Are the pings successful? Why or why not?
_______________________________________________________________________________
b. From external router R2, ping PC-C at IP address 192.168.3.3
Are the pings successful? Why or why not?
_______________________________________________________________________________
212
Task 3. Use the SDM VPN Wizard to Configure the Easy VPN Server
Step 1: Launch the Easy VPN Server wizard and configure AAA services.
a. Click the Configure button at the top of the SDM home screen. Click the VPN task button to view the
VPN configuration page.
b. Select Easy VPN Server from the main VPN window, and then click Launch Easy VPN Server
Wizard.
c. The Easy VPN Server wizard checks the router configuration to see if AAA is enabled. If AAA is not
enabled, the Enable AAA window displays. AAA must be enabled on the router before the Easy VPN
Server configuration starts. Click Yes to continue with the configuration.
d. When prompted to deliver the configuration to the router, click Deliver.
e. In the Command Delivery Status window, click OK. When the message “AAA has been successfully
enabled on the router” displays, click OK.
f. When returned to the Easy VPN Server wizard window, click Next.
213
g. Now that AAA is enabled, you can start the Easy VPN Server wizard by clicking the Launch Easy VPN
Server Wizard button. Read through the descriptions of the tasks that the wizard guides you through.
How does the client receive the IPsec policies? ___________________________________________
How does the Easy VPN remote server configuration differ from the site-to-site?
____________________________________________________________________________________
____________________________________________________________________________________
h. Click Next when you are finished answering the above questions.
Step 2: Configure the virtual tunnel interface and authentication.
a. Select the interface on which the client connections terminate. Click the Unnumbered to radio button
and select the Serial0/0/1 interface from the pull-down menu.
b. Select Pre-shared Keys for the authentication type and click Next to continue.
214
215
Step 3: Select an IKE proposal.
a. In the IKE Proposals window, the default IKE proposal is used for R3.
What is the encryption method used with the default IKE policy? ____________
What is the hash algorithm used to ensure that the keys have not been tampered with? _____________
b. Click Next to accept the default IKE policy.
Note: Configurations on both sides of the tunnel must match exactly. The Cisco VPN Client automatically
selects the proper configuration for itself. Therefore, an IKE configuration is not necessary on the client
PC.
216
Step 4: Select the transform set.
a. In the Transform Set window, the default SDM transform set is used. What ESP encryption method is
used with the default transform set? _________________
b. Click Next to accept the default transform set.
217
Step 5: Specify group authorization and group policy lookup.
a. In the Group Authorization and Group Policy Lookup window, select the Local option.
b. Click Next to create a new AAA method list for group policy lookup that uses the local router database.
218
Step 6: Configure user authentication (XAuth).
a. In the User Authentication (Xauth) window, you can specify to store user information on an external
server, such as a RADIUS server or a local database, or both. Select the Enable User
Authentication check box and accept the default of Local Only.
Where does the router look for valid user accounts and passwords to authenticate remote VPN users
when they attempt to log in?
________________________________________________________________________________
b. Click the Add User Credentials button. In the User Accounts window, you can view currently defined
users or add new users.
What is the name of the user currently defined and what is the user privilege level? ______________
How was this user defined? __________________________________________________________
219
c. In the User Accounts window, click the Add button to add another user. Enter the username VPNuser1
with a password of VPNuser1pass. Select the check box for encrypting the password using the MD5
hash algorithm. Leave the privilege level at 1.
What is the range of privilege level that can be set for a user? _________________________
d. Click OK to accept the VPNuser1 entries, and then click OK to close the User Accounts window.
e. In the User Authentication (XAuth) window, click Next to continue.
220
Step 7: Specify group authorization and user group policies.
In the Group Authorization and User Group Policies window, you must create at least one group policy for
the VPN server.
a. Click Add to create a group policy.
b. In the Add Group Policy window, enter VPN-Access as the name of this group. Enter a new preshared key of cisco12345 and then re-enter it.
c. Leave the Pool Information box checked and enter a starting address of 192.168.3.100, an ending
address of 192.168.3.150, and a subnet mask of 255.255.255.0.
d. Enter 50 for the Maximum Connections Allowed.
e. Click OK to accept the entries.
221
f. An SDM warning message displays indicating that the IP addresses in the pool and the IP address of
the FastEthernet0/1 interface are in the same subnet. Click Yes to continue.
g. When you return to the Group Authorization window, check the Configure Idle Timer check box and
enter one hour (1). This disconnects idle users if there is no activity for one hour and allows others to
connect. Click Next to continue.
222
h. When the Cisco Tunneling Control Protocol (cTCP) window displays, do not enable cTCP. Click Next
to continue.
i. When the Easy VPN Server Passthrough Configuration window displays, make sure that the Action
Modify check box is checked. This option allows SDM to modify the firewall on S0/0/1 to allow IPsec VPN
traffic to reach the internal LAN. Click OK to continue.
223
Step 8: Review the configuration summary and deliver the commands.
a. Scroll through the commands that SDM will send to the router. Do not check the check box to test the
VPN. Click Finish.
b. When prompted to deliver the configuration to the router, click Deliver.
c. In the Command Delivery Status window, click OK. How many commands are delivered? _________
224
Step 9: Test the VPN Server.
a. You are returned to the main VPN window with the Edit Easy VPN Server tab selected. Click the Test
VPN Server button in the lower right corner of the screen.
b. In the VPN Troubleshooting window, click the Start button.
c. Your screen should look similar to the one below. Click OK to close the information window. Click
Close to exit the VPN Troubleshooting window.
225
Task 4. Use the Cisco VPN Client to Test the Remote Access VPN
Step 1: (Optional) Install the Cisco VPN client.
If the Cisco VPN Client software on host PC-A is not installed, install it now. If you do not have the Cisco VPN
Client software, contact your instructor.
Step 2: Configure PC-A as a VPN client to access the R1 VPN server.
a. Start the Cisco VPN Client and select Connection Entries > New, or click the New icon with the red
plus sign (+) on it.
b. Enter the following information to define the new connection entry. Click Save when you are finished.
226
Connection Entry: VPN-R3
Description: Connection to R3 internal network
Host: 10.2.2.1 (IP address of the R3 S0/0/1 interface)
Group Authentication Name: VPN-Access (defines the address pool configured in Task 2)
Password: cisco12345 (pre-shared key configured in Task 2)
Confirm Password: cisco12345
Note: The group authentication name and password are case-sensitive and must match the ones created
on the VPN Server.
Step 3: Test access from PC-A without a VPN connection.
In the previous step, you created a VPN connection entry on the VPN client computer PC-A but have not
activated it, so the VPN tunnel is not yet up.
Open a command prompt on PC-A and ping the PC-C IP address at 192.168.3.3 on the R3 LAN. Are the
pings successful? Why or why not?
____________________________________________________________________________________
____________________________________________________________________________________
Step 4: Establish a VPN connection and log in.
a. Select the newly created connection VPN-R3 and click the Connect icon. You can also double-click
the connection entry.
227
b. Enter the previously created username VPNuser1 in the VPN Client User Authentication dialog box
and enter the password VPNuser1pass. Click OK to continue. The VPN Client window minimizes to a
lock icon in the tools tray of the taskbar. When the lock is closed, the VPN tunnel is up. When it is open,
the VPN connection is down.
Task 5. Verify the VPN Tunnel Between the Client, Server, and Internal Network
Step 1: Open the VPN Client icon.
a. Double-click the VPN lock icon to expand the VPN Client window.
What does it say about the connection status at the top of the window? ________________________
b. From the PC-A command line, issue the ipconfig command.
What is the IP address of the first Local Area Connection? __________________________________
What is the IP address of Local Area Connection 2? _______________________________________
Step 2: Close the VPN connection and reopen it.
a. Click the Disconnect icon in the VPN Client window to close the VPN-R3 connection.
b. Click the Connect icon and log in again as VPNuser1.
228
What is the IP address of Local Area Connection 2 now? __________________________
Note: Each time you disconnect and reconnect to the VPN server, you receive a new IP address until the
limit is reached.
Step 3: Check the tunnel statistics.
a. Select Status > Statistics. Click the Tunnel Details tab.
b. What is the current address obtained from the R3 VPN server and what is the range of addresses that
can be assigned?
______________________________________________________________________________
What is the VPN server address? _____________________
How many packets have been encrypted? ______________
What is the encryption method? ______________________
What is the authentication method? ___________________
c. Leave the VPN Client Statistics window open.
Step 4: Test access from the client PC-A using the VPN connection.
With the VPN connection from computer PC-A to router R3 activated, open a command prompt on PC-A
and ping the PC-C IP address at 192.168.3.3 on the R3 LAN. Are the pings successful? Why or why
not? ________________________________________________________________________
How many packets have now been encrypted? __________________________________________
229
Step 5: Check the Cisco IOS message on R3 when the tunnel is created.
Open the console connection for R3 and locate the message displayed indicating that the virtual interface
came up when the VPN Client connection was made.
What is the name of the interface on R3 that is activated for the VPN? __________________________
Step 6: Verify the VPN connection information for PC-A.
From the PC-A command prompt, issue the ipconfig /all command to see the network connections.
a. What is the configuration for the first Local Area Connection?
IP Address: ________________________________________
Subnet Mask: ______________________________________
Default Gateway: ___________________________________
Description: _______________________________________
b. What is the configuration for Local Area Connection 2?
IP Address: ________________________________________
Subnet Mask: ______________________________________
Default Gateway: ___________________________________
Description: ________________________________________
Step 7: Telnet from PC-A to R3.
From the PC-A command prompt, telnet to R3 at the Fa0/1 IP address 192.168.3.1. Log in as admin01
with a password of admin01pass. What is the router command prompt and why is this?
______________________________________________________________________________
a. Issue the show run command to view the various commands generated by SDM to configure the VPN
Server.
b. Issue the show users command to see connections to router R3. What connections are present?
_____________________________________________________________________________
c. Close the Telnet connection using the quit or exit command.
Task 6. Reflection
Why is VPN a good option for remote users?
Router Interface Summary Table
Router Interface Summary
Router Model
Ethernet Interface
#1
Ethernet Interface
#2
Serial Interface
#1
Serial Interface
#2
1700
Fast Ethernet 0
(FA0)
Fast Ethernet 1
(FA1)
Serial 0 (S0)
Serial 1 (S1)
1800
Fast Ethernet 0/0
(FA0/0)
Fast Ethernet 0/1
(FA0/1)
Serial 0/0/0
(S0/0/0)
Serial 0/0/1
(S0/0/1)
2600
Fast Ethernet 0/0
(FA0/0)
Fast Ethernet 0/1
(FA0/1)
Serial 0/0 (S0/0)
Serial 0/1 (S0/1)
230
Router Interface Summary
2800
Fast Ethernet 0/0
(FA0/0)
Fast Ethernet 0/1
(FA0/1)
Serial 0/0/0
(S0/0/0)
Serial 0/0/1
(S0/0/1)
Note: To find out how the router is configured, look at the interfaces to identify the type of router
and how many interfaces the router has. There is no way to effectively list all the combinations of
configurations for each router class. This table includes identifiers for the possible combinations of
Ethernet and Serial interfaces in the device. The table does not include any other type of interface,
even though a specific router may contain one. An example of this might be an ISDN BRI interface.
The string in parenthesis is the legal abbreviation that can be used in Cisco IOS commands to
represent the interface.
231
Download PDF
Similar pages