How VPN Works? 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 even around the world. But there is one thing that all companies need: a way to maintain fast, secure, and reliable communications wherever their offices are located.
Until recently, reliable communication has meant the use of leased lines to maintain a wide-area network (WAN). Leased lines, ranging from Integrated Services Digital Network (ISDN, which runs at 144 Kbps) to Optical Carrier-3 (OC3, which runs at 155 Mbps) fiber, provide a company with a way to expand their private network beyond their immediate geographic area. A WAN has obvious advantages over a public network like the Internet when it comes to reliability, performance, and security; but maintaining a WAN, particularly when using leased lines, can become quite expensive (it often rises in cost as the distance between the offices increases). Additionally, leased lines are not a viable solution for organizations where part of the work force is highly mobile (as is the case with the marketing staff) and might frequently need to connect to the corporate network remotely and access sensitive data.
As the popularity of the Internet has grown, businesses have turned to it as a means of extending their own networks. First came intranets, which are sites designed for use only by company employees. Now, many companies create their own Virtual Private Networks (VPNs) to accommodate the needs of remote employees and distant offices.
A typical VPN might have a main local-area network (LAN) at the corporate headquarters of a company, other LANs at remote offices or facilities, and individual users that connect from out in the field.
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.