Nortel Networks WAG54G - Manual (Page 13)

6 Chapter 2: Planning Your Network
Why do I need a VPN?
Wireless-G ADSL Gateway
telecommuters, and/or professionals on the road (travelers can connect to a VPN Gateway using any computer
with VPN client software that supports IPSec, such as SSH Sentinel.)
There are two basic ways to create a VPN connection:
• VPN Gateway to VPN Gateway
• Computer (using VPN client software that supports IPSec) to VPN Gateway
The VPN Gateway creates a “tunnel” or channel between two endpoints, so that data transmissions between
them are secure. A computer with VPN client software that supports IPSec can be one of the two endpoints. Any
computer with the built-in IPSec Security Manager (Microsoft 2000 and XP) allows the VPN Gateway to create a
VPN tunnel using IPSec. Other versions of Microsoft operating systems require additional, third-party VPN client
software applications that support IPSec to be installed.
Computer (using VPN client software that supports IPSec) to VPN Gateway
The following is an example of a computer-to-VPN Gateway VPN: In her hotel room, a traveling businesswoman
dials up her ISP. Her notebook computer has VPN client software that is configured with her office's VPN settings.
She accesses the VPN client software that supports IPSec and connects to the VPN Gateway at the central office.
As VPNs utilize the Internet, distance is not a factor. Using the VPN, the businesswoman now has a secure
connection to the central office's network, as if she were physically connected.
VPN Gateway to VPN Gateway
An example of a VPN Gateway-to-VPN Gateway VPN would be as follows: At home, a telecommuter uses his VPN
Gateway for his always-on Internet connection. His Gateway is configured with his office's VPN settings. When he
connects to his office's Gateway, the two Gateways create a VPN tunnel, encrypting and decrypting data. As VPNs
utilize the Internet, distance is not a factor. Using the VPN, the telecommuter now has a secure connection to the
central office's network, as if he were physically connected.
For additional information and instructions about creating your own VPN, please visit Linksys's international Web
site at http://www.linksys.com/international/.
Why do I need a VPN?
Computer networking provides a flexibility not available when using a paper-based system. With this flexibility,
however, comes an increased risk in security. This is why firewalls were first introduced. Firewalls help to protect
data inside of a local network. But what do you do once information is sent outside of your local network, when