A virtual private network also known as a VPN is a private network that extends across a public network or internet. It enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network.
VPNs can provide functionality, security and/or network management benefits to the user. But they can also lead to new issues, and some VPN services, especially “free” ones, can actually violate their users’ privacy by logging their usage and making it available without their consent, or make money by selling the user’s bandwidth to other users.
Some VPNs allow employees to securely access a corporate intranet while located outside the office. Some can securely connect geographically separated offices of an organization, creating one cohesive network. Individual Internet users can use some VPNs to secure their wireless transactions, to circumvent geo-restrictions and censorship, and/or to connect to proxy servers for the purpose of protecting personal identity and location. But some Internet sites block access via known VPNs to prevent the circumvention of their geo-restrictions.
A VPN is created by establishing a virtual point-to-point connection through the use of dedicated connections, virtual tunnelling protocols, or traffic encryption. 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.
Traditional VPNs are characterized by a point-to-point topology, and they do not tend to support or connect broadcast domains, so services such as Microsoft Windows NetBIOS may not be fully supported or work as they would on a local area network (LAN). Designers have developed VPN variants, such as Virtual Private LAN Service (VPLS), and layer-2 tunneling protocols, to overcome this limitation.