A virtual private network (VPN) is a private communications network usually used within a company, or by several different companies or organizations, to communicate over a wider network. VPN message traffic can be carried over a public networking infrastructure (e.g. the Internet) on top of standard protocols, or over a service provider's private network with a defined Service Level Agreement (SLA) between the VPN customer and the VPN service provider.
Many VPN client programs can be configured to require that all IP traffic must pass through the tunnel while the VPN is active, for better security. From the user's perspective, this means that while the VPN client is active, all access outside their employer's secure network must pass through the same firewall as would be the case while physically connected to the office ethernet. This reduces the risk that an attacker might gain access to the secured network by attacking the employee's laptop: to other computers on the employee's home network, or on the public internet, it is as though the machine running the VPN client simply does not exist. Such security is important because other computers local to the network on which the client computer is operating may be untrusted or partially trusted. Even with a home network that is protected from the outside internet by a firewall, people who share a home may be simultaneously working for different employers over their respective VPN connections from the shared home network. Each employer would therefore want to ensure their proprietary data is kept secure, even if another computer in the local network gets infected with malware. And if a travelling employee uses a VPN client from a Wi-Fi access point in a public place, such security is even more important. However, the use of IPX/SPX is one way users might still be able to access local resources.
More on [ Virtual private network ]
Data Communications
Remote Access :: Networking

About.com VPN directory - A smattering of VPN resources including a glossary and a self-test.
Meta Description: [ VPN solutions support remote access and private data communications over public networks as a cheaper alternative to leased lines. VPN clients communicate with VPN servers utilizing a number of specialized protocols. ]
Corecom VPN FAQ Page - Geared towards those new to VPN.
Find VPN - Directory of VPN providers, articles, and links.
Meta Description: [ Up to the minute news and resources covering VPN (Virtual Private Networks). Sign up for the daily VPN news alert. ]
How Stuff Works: How Virtual Private Networks Work - Gives definition of VPN and an overview of general VPN topics, includes diagrams and an animation.
Meta Description: [ How can your offices in Milan, Paris and San Francisco maintain fast, secure and reliable communications with the main office and each other? Virtual private networks give companies a way to extend their secure networks using regular Internet pathways. Find out how remote users can access a local... ]
500
InfoSysSec - Comprehensive collection of VPN guides, FAQs, tutorials and articles. Vendors and products; usage with Linux, NT and Unix; integration with firewalls, and mailing lists.
NW Fusion: Research: VPNs - This is a comprehensive collection of VPN resources and articles.
Tom Dunigan's Virtual Private Networks page - This page describes IP-based VPN technology over the Internet
Virtual Private Network Consortium - VPNC is the international trade association for manufacturers in the VPN market.
Meta Description: [ Virtual Private Network Consortium -- VPNC ]
VPN Info on the World Wide Web - All-encompasing guide to VPN. Includes standards, reviews, legal information, and howtos.
VPN labs - research community - VPN labs is an open community for researching, reviewing, and discussing Virtual Private Networks.
Meta Description: [ VPN labs is an open community for researching, testing, reviewing, and discussing Virtual Private Networks. ]
| How to setup a VPN | |
| Next Video | |