virtual private network

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virtual private network

[¦vər·chə·wəl ‚prī·vət ′net‚wərk]
(communications)
A wide-area network whose links are provided by a common carrier although they appear to the users to behave like dedicated lines, and whose computers use a common cryptographic key to send messages from one computer in the network to another. Abbreviated VPN.

Virtual Private Network

(networking, security)
(VPN) The use of encryption in the lower protocol layers to provide a secure connection through an otherwise insecure network, typically the Internet. VPNs are generally cheaper than real private networks using private lines but rely on having the same encryption system at both ends. The encryption may be performed by firewall software or possibly by routers.

Link-level (layer 2 and 3) encryption provides extra protection by encrypting all of each datagram except the link-level information. This prevents a listener from obtaining information about network structure. While link-level encryption prevents traffic analysis (a form of attack), it must encrypt/decrypt on every hop and every path.

Protocol-level encryption (layer 3 and 4) encryption encrypts protocol data but leaves protocol and link headers clear. While protocol-level encryption requires you to encrypt/decrypt data only once, and it encrypts/decrypts only those sessions that need it, headers are sent as clear text, allowing traffic analysis.

Application (layer 5 up) encryption is based on a particular application and requires that the application be modified to incorporate encryption.

Cisco.

virtual private network

A private network configured within a public network such as the Internet or a carrier's network. Years ago, virtual private networks (VPNs) obsoleted private lines between company branches. Using data encryption to maintain privacy, VPNs also allow mobile users access to the company LAN.

In the past, common carriers used their vast networks to "tunnel" traffic between customer locations to give the appearance of a private network while sharing backbone trunks, no different than the way the Internet works. Prior to the Internet's IP protocol, VPNs were built over X.25, Switched 56, frame relay and ATM technologies. See PVC, SVC, computer security and information security.

Internet VPNs
Internet VPNs are very popular, and several security protocols are used. IPsec, L2TP and PPTP provide secure tunnels over the Internet. For brief transactions at a Web site, SSL is widely used. See IPsec, L2TP, PPTP and SSL.

Virtual IP VPNs from Carriers
A "virtual private routed network" (VPRN) connects the customer's IP router to the provider's IP router. See MPLS.

Ethernet VPNs from Carriers
Carriers encapsulate Ethernet frames in one location and deliver them to another. Connecting two Ethernets is a "LAN interconnect service," while multipoint connectivity is a "transparent LAN service" (TLS). A "virtual private LAN service" (VPLS) is a multipoint VPN using an IP/MPLS core to route traffic. See TLS, VPLS and IP/MPLS core.

Frame Relay VPNs from Carriers
Carriers have offered frame relay point-to-point and multipoint VPNs, whereby the customer's equipment converts internal IP packets to frame relay packets. Adding a location in such a network means provisioning virtual circuits from the new site to all the other sites. See frame relay.
References in periodicals archive ?
Following the launch of its SSL-VPN technology in the fourth quarter of 2005, SonicWALL has achieved #1 position in worldwide unit share for SSL VPN gateways in the first quarter of 2006 and sustained its #1 market share position in Q2, according to Infonetics Research's Network Security Appliances and Software Reports.
2004 was a period of rapid growth in the SSL VPN market.
However, presently, the SSL VPN vendors provide much more sophisticated access methods,including increased mobile device support and enhanced endpoint security tools.
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I'm a Mac user myself, and I use the Aventail SSL VPN everyday when I access my email, financial data, or CRM applications from home on my Mac--and it works every time without any extra work from my IT staff.
During the VPNC certification process, StoneGate SSL VPN proved to be interoperable with other technologies and products.
The SSL VPN Pavilion will provide vendors with a great opportunity to interact with buyers who are eager to learn about the latest products and services.
Aventail is the most experienced SSL VPN vendor; and they are a tough competitor in this space because they have a large installed base of customers and years of experience with the technology and customer problems; their combined product and service revenue make them a clear leader in this market," the report stated.
Using its patented Intelligent Connection Acceleration Architecture (ICAA[TM]) and overhead-reducing Transparent SSL (TSSL[TM]) engine, SSL VPN-Plus addresses the fundamental performance degradation found in every SSL VPN solution.
The world's largest and most respected service providers have built their SSL VPN businesses on Aventail's technology, including AT&T, IBM Global Services, Infonet, MCI, NextCom, SITA SC, and many others, who use Aventail's platform as the foundation of their managed SSL VPN services business.
As one of the first vendors to earn ICSA Labs' certification, F5 has demonstrated its commitment to provide SSL VPN solutions that meet the highest standards in security," said Brian Monkman, Technology Programs Manager at ICSA Labs.
com) (NASDAQ: FFIV), the global leader in Application Delivery Networking, today announced an enhanced version of its award-winning FirePass[R] Controller SSL VPN (http://www.