Virtual Private Networks
A virtual private network (VPN) enables IP traffic to travel securely over a public TCP/IP network by encrypting all traffic from one network to another. A VPN uses “tunneling” to encrypt all information at the IP level.
VPN is very loosely defined as a network in which a customer or end user connects to one or more sites through a public infrastructure, such as the Internet or World Wide Web.
We have already discussed dialup VPNs or Virtual Private Dialup Network (VPDN) in Chapter 5, “Security Protocols.”
VPNs are typically set up permanently between two or more sites. Figure 7-6 displays a typical VPN design.
Figure 7-6. VPN Model
Figure 7-6 displays a typical hub (central site) to spoke (remote site) model, where ...