A virtual private network (VPN) is a computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger network (e.g., the Internet) instead of by physical wires. The link-layer protocols of the virtual network are said to be tunneled through the larger network when this is the case. One common application is secure communications through the public Internet, but a VPN need not have explicit security features, such as authentication or content encryption. VPNs, for example, can be used to separate the traffic of different user communities over an underlying network with strong security features.
- Remote Access VPN.
- SSL /web based RA-VPN.
- Client based RA-VPN.
- Site to Site VPN.
VPN connection types.
The key benefits that VPN technologies provide are:
- Extend geographic connectivity
- Greatly reduce operational costs when compared to traditional WAN technologies
- Improve productivity
- Provide support for home/remote working
- Integrate well with existing broadband access technologies
They key functions which make VPN technologies secure are the following:
- Authentication - Ensuring the communication is from a trusted source
- Access Control - Preventing unauthorised users from accessing the network
- Confidentiality - Preventing the reading or copying of data as it travels across the public network
- Data integrity - Ensuring the data has not been tampered with as it travels across the public network