A virtual private network (VPN) extends a private network across
a public network and enables users to send and receive data
across shared or public networks as if their computing devices
were directly connected to the private network. Applications
running across a VPN may therefore benefit from the
functionality, security, and management of the private network.
It provides access to resources that may be inaccessible on the
public network, and is typically used for telecommuting workers.
Encryption is a common, although not an inherent, part of a VPN
connection. A VPN is created by establishing a virtual
point-to-point connection through the use of dedicated circuits
or with tunneling protocols over existing networks. A VPN
available from the public Internet can provide some of the
benefits of a wide area network (WAN). From a user perspective,
the resources available within the private network can be
accessed remotely.
A host-to-network configuration is analogous to connecting a computer to a local area network. This type provides access to an enterprise network, such as an intranet. This may be employed for telecommuting workers who need access to private resources, or to enable a mobile worker to access important tools without exposing them to the public Internet.
A site-to-site configuration connects two networks. This configuration expands a network across geographically disparate offices, or a group of offices to a data center installation. The interconnecting link may run over a dissimilar intermediate network, such as two IPv6 networks connected over an IPv4 network.