Chapter 3. VPNs and Tunneling

A Virtual Private Network (VPN) enables computers connected via an insecure network (for example, the Internet) to establish secure connections to work on a private network using a virtual point-to-point connection that prevents eavesdropping by external parties. VPN technologies guarantee security and privacy on the communication using various techniques of authentication and encryption. As soon as the computer or user is connected through a virtual channel, they can benefit from the additional reliability of the internal network, including network policies and security controls dedicated to the endpoints. The VPN client has a level of access to data that is usually reserved for a LAN client. VPN technologies are also widely used for another purpose: to secure connection between multiple offices in different geographical locations. In such a scenario we are using a low cost data network (public or shared), without compromising the trustworthiness of the information...