Linksys AG241 Why do I need a VPN?

Chapter 2: Planning Your Network

Why do I need a VPN?

ADSL2 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 C: 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.

The following is an example of a computer-to-VPN Gateway VPN. (See Figure 2-2.) 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 Gate-

way 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.

An example of a VPN Gateway-to-VPN Gateway VPN would be as follows. (See Figure 2-3.) 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

website at www.linksys.com/international or refer to “Appendix C: Configuring IPSec between a Windows 2000 or

XP computer and the VPN Gateway.”

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

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.

Figure 2-2: Computer-to-VPN Gateway