Virtual Private Networks (VPNs) are an easy and cost effective way to connect two or more networks over the Internet. This is achieved by using encrypted tunnels for security and efficiency. VPNs use encapsulated and encrypted IP packets and transport them across leased Local Area Network (LAN) lines.The benefits of using VPNs are reduced cost overhead, reduced management overhead, and added security (Microsoft Press, 2000). Least network lines are expensive and VPNs reduce then need for extra data connections. This in turn also aids in reducing the amount of overhead associated with managing a network. The added security benefits for a network include encrypted transmission of network data and user authentication.Passing datagrams across the Internet between sites can cause major security risk. When a datagram is passed internally within a private network it is secured behind a router and /or firewall. When datagrams are passed externally outsiders can monitor them as they pass over networks owned by other organizations (Comer, 1995). This can cause great security problems. Unencrypted packet headers contain valuable information about the internal structure of an organizations network.VPNs have overcome the problem of direct Internet access to servers and clients through a combination of the following security components: IP encapsulation, cryptographic authentication, and data payload encryption. For a true VPN to exist, it must contain all three of these components (Strebe, Matthew & Perkins, Charles, 2000). While payload encryption and cryptographic authentication may seem like the same thing, they are not. Cryptographic authentication is used for remote user authentication. Windows and Unix platforms can both provide for this function. While payload encryption is used for encrypting the data that is sent within the packet. An example of data payload encryption is Secure Socket Layer (SSL). SSL can encrypt data with...
