A virtual private network (VPN) is a communications network tunneled through another network, and dedicated for a specific network. In that sense, the network is “virtual” because it may span various physical networks. A VPN can take use of various security measures to ensure that communication is kept private and secure, even when the VPN uses a public network such as the Internet.

Using a VPN, a Network Administrator can enable a user to access a corporation’s computer resources from home. Users can establish a VPN connection using the Internet or a private phone line over a public exchange. Thus, one can retrieve their work email from home.

A VPN can also be used to separate the traffic of different user communities over an underlying network with strong security features. For instance, a factory that only has one network cable to connect all computers might use multiple VPNs to separate the different user types and resources.

A VPN is commonly used to enable OPC communication between users and remote data sources.

See also: WAN