A VPN supplies network connectivity over a possibly long physical distance. In this respect, a VPN is a form of Wide Area Network (WAN). VPNs enable file sharing, video conferencing and similar network services. Virtual private networks generally don't provide any new functionality that isn't already offered through alternative mechanisms, but a VPN implements those services more efficiently / cheaply in most cases.
A key feature of a VPN is its ability to work over both private networks as well as public networks like the Internet. Using a method called tunneling, a VPN use the same hardware infrastructure as existing Internet or intranet links. VPN technologie includes various security mechanisms to protect the virtual, private connections. Specifically, a VPN supports at least three different modes of use:
- ⇨Internet remote access client connections
- ⇨LAN-to-LAN internetworking
- ⇨Controlled access within an intranet