VPN

VPN

 Virtual Private Network

The world has changed a lot in the last couple of decades. Instead of simply dealing with local or regional concerns, many businesses now have to think about global markets and logistics. Many companies have facilities spread out across the country or around the world, and there is one thing that all of them need: A way to maintain fast, secure and reliable communications wherever their offices are.

 

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As the popularity of the Internet grew, businesses turned to it as a means of extending their own networks. First came intranets, which are password-protected sites designed for use only by company employees. Now, many companies are creating their own VPN (virtual private network) to accommodate the needs of remote employees and distant offices.

Basically, a VPN is a private network that uses a public network (usually the Internet) to connect remote sites or users together. Instead of using a dedicated, real-world connection such as leased line, a VPN uses "virtual" connections routed through the Internet from the company's private network to the remote site or employee. In this article, you will gai­n a fundamental understanding of VPNs, and learn about basic VPN components, technologies, tunneling and security.

Virtual private networks help distant colleagues work together, much like desktop sharing

A virtual private network (VPN) is a private datanetwork that makes use of the public telecommunication infrastructure,maintaining privacy through the use of a tunneling protocol and securityprocedures. A virtual private network can be contrasted with a system of ownedor leased lines that can only be used by one company. The main purpose of a VPNis to give the company the same capabilities as private leased lines at muchlower cost by using the shared public infrastructure. Phone companies haveprovided private shared resources for voice messages for over a decade. Avirtual private network makes it possible to have the same protected sharing ofpublic resources for data. Companies today are looking at using a privatevirtual network for both extranets and wide-area intranets.
Before the Internet became nearly-universal, a virtual private networkconsisted of one or more circuits leased from a communications provider.Each leased circuit acted like a single wire in a network that wascontrolled by customer. The communications vendor would sometimes alsohelp manage the customer's network, but the basic idea was that acustomer could use these leased circuits in the same way that they usedphysical cables in their local network.

The privacy afforded by these legacy VPNs was only that thecommunications provider assured the customer that no one else would usethe same circuit. This allowed customers to have their own IP addressingand their own security policies. A leased circuit ran through one ormore communications switches, any of which could be compromised bysomeone wanting to observe the network traffic. The VPN customer trustedthe VPN provider to maintain the integrity of the circuits and to usethe best available business practices to avoid snooping of the networktraffic. Thus, these are called trusted VPNs.
A Virtual Private Network (VPN) involves transmitting private data overpublic networks. It is not a new term for data communications. The termVPN initially came from the specific carrier's design, where a part ofthe carrier's network (referred to as a cloud) is separated from otherparts and is leased by an enterprise for purposes of voice, data, andvideo communications.

As the Internet became more popular as a corporate communicationsmedium, security became much more of a pressing issue for both customersand providers. Seeing that trusted VPNs offered no real security,vendors started to create protocols that would allow traffic to beencrypted at the edge of one network or at the originating computer,moved over the Internet like any other data, and then decrypted when itreached the corporate network or a receiving computer. This encryptedtraffic acts like it is in a tunnel between the two networks: even if anattacker can see the traffic, they cannot read it, and they cannotchange the traffic without the changes being seen by the receiving partyand therefore rejected. Networks that are constructed using encryptionare called secure VPNs.

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