VPN Basic Introduction VPN Types

VPN Basic Introduction VPN Types
VPN Basic
To enterprise, the security of confidential information is a great issue for a company. In modern
society, mobile devices are popular and people who work with mobile devices also increase
more and more. IT administrators not only assure the stability and convenience of the
communication between business men and cooperative partners outside, but also maintain the
security of remote access for the both sites. Therefore, how to protect the information is the big
challenge for IT administrators.
A Virtual Private Network (VPN) is the extension of a private network that encompasses links
across shared or public networks like the Internet. In short, by VPN technology, you can send
data between two computers across a shared or public network in a manner that emulates the
properties of a point-to-point private link.
VPN Types
The common VPN types are listed as below:
Before constructing the network connection, users must be authorized to ensure the information
be encrypted and transmitted safely on both sites. Such type can provide a secure and cost
effective method to assist the enterprises building remote connection securely all over the world.
And it can offer a reliable network connection for the data exchange from site to site or clients
to site. However, remote clients have to install relational IPSec software for the configuration of
Windows IPSec will be complicated. In addition, the users must face the compatibility problem
caused by NAT traversal constructed by IPSec application software, router and IPsec gateway.
These are the disadvantages that the IPSec users must face.
The feature of PPTP (Point-to-Point Tunneling Protocol) tunneling technique is easy to
configure, therefore, it is a protocol that is used widely by people. Through PPTP VPN, the user
can use the network connection built in Windows operation system to establish a virtual private
PPTP will encapsulate the data with IP packets and transmit to the destination via Internet. The
packets encapsulated will be regarded as common IP packets by any router, device or machine
in network and be sent out. When the packets arrived to remote end of the VPN tunnel, the
header of the IP packets encapsulated will be removed. The advantage of such technique is that
the data with different protocols can be transmitted through any network media (e.g., Internet)
supporting IP.
SSL VPN (Secure Sockets Layer virtual private network) is a form of VPN that can be used
with a standard Web browser. That’s, it is a web-based and non-client software. It is not
necessary for users to pre-install any VPN client software (e.g, SmartVPN). Meanwhile, it will
not be restricted by network environment and it is easy to configure and simple to be
maintained through webpages. Most important, it is cost saving. What advantages that SSL
VPN have?
First, general web browsers support such protocol. It is not necessary for users to install
software to configure settings additionally. The management requirement fee can be
reduced largely.
Second, the administrator can configure several policies to make the remote clients
accessing data via Internet safely.
Finally, the application of browser will not be influenced or blocked by the firewall.
Therefore, it can avoid the situation that VPN is unavailable due to the firewall
DrayTek VPN Solutions
At present, the models which support fully VPN functions contain Vigor2950, Vigor2930 and
Vigor2930n. Here we focus on SSL VPN. The main applications for SSL VPN that DrayTek
VPN solution provides are:
SSL Web Proxy
SSL Web Proxy will allow the remote user(s) to access into the internal system (e.g., ERP
system, G-forge system, etc.) over HTTPS. Refer to the following figure for an example:
As shown in above figure, for the server end, the administrator must specify account(s) and
password(s) for remote dial-in user and server profiles (URL); and for the remote user end,
what he/she has to do is to obtain server IP address, account and password from system
SSL Tunnel
It allows the remote users to make an SSL VPN Tunnel connection (which will not be blocked
by any firewall or transferred by NAT) through Internet, suitable for the application through
network accessing (e.g., e-mail server or FTP server). Refer to the following figure for an
Access the desktop of a remote PC via SSL VPN
To access the desktop of a remote PC which is behind a NATed router, you have two options.
One is by opening relative ports (e.g. TCP 5900 for VNC or TCP 3389 for RDP) on the router,
the other is by connecting a VPN tunnel to the router. The former is easy but not secure as the
router is exposed to the whole Internet. Furthermore it’s hard to add security by using firewall
policies to restrict the accessing IP addresses for mobility users. As for the latter method based
on VPN connection, it provides security by requiring you to build a tunnel to the router before
accessing the internal computers and the tunnel may be encrypted. There are three types of
VPN connection:
Connect a tradition VPN connection to the office, such as PPTP, L2TP or IPSec.
Connect a SSL Tunnel to the office.
Connect a SSL VPN to the office.
With the above said method 1 and 2 you have full access to the whole office network, whereas
with the method 3 you will be restricted to specific applications.
Vigor2950 now supports VNC and RDP applications and acts as VNC/RDP client. You can
connect a computer to Vigor2950 via SSL VPN by using a web browser, such as IE or Firefox,
then access the desktop of a computer connected behind Vigor2950 and running the VNC or
RDP server.
Remote Access Control
In remote access control setup, there are several VPN services provided by DrayTek routers and
the operation is easy, too. Simply enable the necessary VPN service as you need. If you intend
to run a VPN server inside your LAN, you should disable the VPN service of Vigor Router to
allow VPN tunnel pass through, as well as the appropriate NAT settings, such as DMZ or open
To sum up, SSL VPN resolutions provided by DrayTek can make people use the network
resources more conveniently and safely. The remote users do not need to install any client
software onto their computers additionally, and they can access the network for getting
information via standard Internet browsers at any time. SSL VPN has the same advantage in
data security as IPSec, however it does not own the shortcoming of IPSec. In addition, it can
solve the compatibility problem caused by using NAT. Welcome visit DrayTek website to get
more detailed product information: www.draytek.com.
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