Cisco Systems RVS4000RF manual What is a VPN?

Planning Your Virtual Private Network (VPN)	3
What is a VPN?

What is a VPN?

A VPN, or Virtual Private Network, is a connection between two endpoints—a VPN router, for instance—in different networks that allows private data to be sent securely over a shared or public network, such as the Internet. This establishes a private network that can send data securely between these two locations or networks.

This is done by creating a “tunnel”. A VPN tunnel connects the two PCs or networks and allows data to be transmitted over the Internet as if it were still within those networks. Not a literal tunnel, it is a connection secured by encrypting the data sent between the two networks.

VPN was created as a cost-effective alternative to using a private, dedicated, leased line for a private network. Using industry standard encryption and authentication techniques—IPSec, short for IP Security—VPN creates a secure connection that, in effect, operates as if you were directly connected to your local network. You can use VPN to create a secure network that links a central office with branch offices, telecommuters, and/or professionals on the road (travelers can connect to a VPN router by using any computer with the Cisco QuickVPN Client software).

There are two basic ways to create a VPN connection:

•VPN router to VPN router

•Computer (using the Cisco QuickVPN Client software) to VPN router

The VPN router creates a “tunnel” or channel between two endpoints, so that data transmissions between them are secure. A computer with the Cisco QuickVPN Client software can be one of the two endpoints (refer to Appendix B, “Using Cisco QuickVPN for Windows 2000, XP, or Vista”). If you choose not to run the VPN client software, any computer with the built-in IPSec Security Manager (Microsoft 2000 and XP) allows the VPN router to create a VPN tunnel by using IPSec (refer to Appendix C, “Configuring IPSec with a Windows 2000 or XP Computer”). Other versions of Microsoft operating systems require additional, third-party VPN client software applications that support IPSec to be installed.

Cisco RVS4000 Security Router with VPN Administrator Guide 15