VPN Overview

Virtual private networking (VPN) involves the creation of secured, point-to-point connections across a private network or a public network, such as the Internet. A VPN client uses special TCP/IP-based protocols called tunneling protocols to make a virtual call to a virtual port on a virtual private networking server. The best example of virtual private networking is that of a VPN client who makes a VPN connection to a remote access server that is connected to the Internet. The remote access server answers the virtual call, authenticates the caller, and transfers data between the VPN client and the corporate network.

VPN uses one network to connect the components of another. The basic technology that defines a VPN is tunneling. Tunneling is the method of transferring data over the Internet or other public network, providing security and features formerly available only on private networks. A tunneling protocol encapsulates the data packet in a header that provides routing information to enable the encapsulated payload to securely traverse the network. The entire process of encapsulation and transmission of packets is tunneling, and the logical connection through which the packets travel is the tunnel.