Section 4.4: Virtual Private Networks
A virtual private network (VPN) is a private network connection between two networks across the internet, as shown in Figure 63. It is a secure connection over an unsecure environment. With a VPN, the two remote networks appear to have connected locally. It requires VPN software running on the servers and workstations in both the networks and may also require a special hardware.
VPN uses tunneling protocols such as Layer2 Tunneling Protocol (L2TP), IPSec, and Point-to-Point Tunneling Protocol (PPTP). VPNs are generally used to connect two or more remote offices securely or make a connection between private networks across a public network. VPN uses encryption while transmitting data from one end point to another and provides higher levels of security.