With the Point-to-Point
Tunneling Protocol (PPTP) or Layer Two Tunneling Protocol (L2TP), which are
automatically installed on your computer, you can securely access resources on a
network by connecting to a remote access server through the Internet or other
network. The use of both private and public networks to create a network
connection is called a virtual private network (VPN). The following table
describes the advantages of using VPN connections.
|
Advantage |
Example |
|
Cost
advantages |
The
Internet is used as a connection instead of a long distance telephone
number or 1-800 service. Because an ISP maintains communications hardware
such as modems and ISDN adapters, your network requires less hardware to
purchase and manage. |
|
Outsourcing
dial-up networks |
You
can make a local call to the telephone company or Internet service
provider (ISP), which then connects you to a remote access server and your
corporate network. It is the telephone company or ISP that manages the
modems and telephone lines required for dial-up access. Because the ISP
supports complex communications hardware configurations, a network
administrator is free to centrally manage user accounts at the remote
access server. |
|
Enhanced
security |
The
connection over the Internet is encrypted and secure. The remote access
server enforces new authentication and encryption protocols. Sensitive
data is hidden from Internet users, but made securely accessible to
appropriate users through a VPN. |
|
Network
protocol support |
Because
the most common network protocols (including TCP/IP and IPX) are
supported, you can remotely run any application dependent upon these
particular network protocols. The IPX/SPX protocol is not available on
Windows XP 64-Bit Edition. |
|
IP
address security |
Because
the VPN is encrypted, the addresses you specify are protected, and the
Internet only sees the external IP address. For organizations with
nonconforming internal IP addresses, the repercussions of this are
substantial, as no administrative costs are associated with having to
change IP addresses for remote access via the Internet. |
|
VPNs
and The Internet |
|
|
|
|
1). VPNs through the ISP
By
making a private connection through the network provided by your ISP. In
this case no additional hardware is required but you must use the same ISP
at both ends of the connection. In this example, the
VPN connection makes a call to the remote access server through the VPN gateway
setup at the ISP. After authentication, you can access
the corporate network, as shown in the following illustration.
This option is available through Cybertronic.net for an additional $50 per month per connection with the internet connections we sell. This user makes use of the full-time, high speed SDSL or T1 internet connection setup for them at their remote location.
2). VPNs over the Internet
The
second method does not require using the same ISP on both ends. The VPN
tunnel is created by connecting through the Internet as shown in the following examples.
When the dial-up client
calls the ISP, it adds a default route using the connection to the ISP as shown
in following figure. At this point, it can reach all Internet addresses through
the router at the ISP NAS.
When the VPN client creates the VPN connection, another default route and a host route to the IP address of the tunnel server are added, as illustrated in the next figure.
Default Route Created
When Initiating the VPN
In the second example, the
VPN connection is made through the tunnel established to the VPN gateway server
that Cybertronic.Net sets up at your office. Examples of this type of user include a
person whose computer is connected through a modem, a local area network, a cable modem user,
or a subscriber of a service such as ADSL, where IP connectivity is established
immediately after the user's computer is turned on. The PPTP or
L2TP driver
makes a tunnel through the Internet and connects to the PPTP-enabled or
L2TP-enabled remote access server. After authentication, the user can access the
corporate network, achieving the same functionality as the preceding example.
Note
·
Connecting
directly to the Internet means direct IP access without going through an
ISP.
(For example, some hotels allow you to use an Ethernet cable to connect to the
Internet.)
·
If you have an
active Winsock Proxy client, you cannot create a VPN. A Winsock Proxy client
immediately redirects data to a configured proxy server before the data can be
processed in the fashion required by a VPN. To establish a VPN, the Winsock Proxy
client should be disabled.
Last maintained on Friday, December 18, 2009.
