VPN
A VPN, or Virtual Private Network, is a connection between two computers in different networks that allows private data to be sent securely over a shared or public network, such as the Internet. VPN establishes a private network so that data can be sent securely between these two locations. This direct link or "tunnel" allows all the applications that are located on the main network to be accessible from the remote location. For example, you could access your corporate email account, server-based files, and other critical business applications from your home or away on travel. You can work exactly the same as if you are in the office, because from the application's perspective there is no difference between a device directly connected to the main network and one connected through VPN.
VPNs provide a quick, easy and cost effective way to enable remote users to take all of their business applications on the road with them. Instead of using a dedicated connection such as a leased line, a VPN uses "virtual" connections through the Internet to create a secure connection from the company private network to the employee. VPNs are used to create secure networks linking a central office with branch offices, telecommuters, and/or professionals on the road (business travelers can connect to a VPN router using any computer with VPN client software that supports IPSec). IPSec (Internet Protocol Security) is a set of standards used to exchange secure data packets, and is commonly used for implementing VPNs.
There are two basic ways to create a VPN connection:
1. VPN Router to VPN Router
At home, a telecommuter uses his Cable/DSL VPN Router for his always-on Internet connection. He has configured his router with his office's VPN settings. When he connects to his office's router, the two routers create a VPN tunnel, encrypting and decrypting data. Since 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.
2. Computer (using VPN client software or USB adapter that supports IPSec) to VPN Router
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 runs the VPN client software that supports IPSec (Internet Protocol Security) and connects to the VPN Router at the central office. Since 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 Security
VPNs are used to secure the actual transmission of information from one specific place to another specific place over the Internet. The idea is to secure the data when it is in a public place (the Internet) where hackers or anyone else could access it, but is generally left unencrypted while it is in a private network under your control (the corporate network at your office). With the proper login and VPN software installed, only authorized users can access the corporate network through the Internet and any data that is exchanged cannot be intercepted.