Why do I need a VPN?

ADSL Gateway with 4-Port Switch

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 (refer to “Appendix B: Configuring IPSec between a Windows 2000 or XP computer and the VPN Gateway”). 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 con- nection 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 website at www.linksys.com or refer to “Appendix C: Configuring IPSec between a Windows 2000 or XP computer and the VPN Gateway.”

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

Chapter 2: Planning your Network

Figure 2-2: Computer-to-VPN Gateway

IMPORTANT: You must have at least one VPN Gateway on one end of the VPN tunnel. At the other end of the VPN tunnel, you must have a second VPN Gateway or a computer with VPN client software that supports IPSec.

Why do I need a VPN?