VPN Defined

Imagine you witness a security carrier with a briefcase attached to his wrist by a set of handcuffs. You can't help but wonder what is inside the briefcase. It could be government documents, it could be money, or it could be nothing. Such is the nature of modern secure Virtual Private Networks (VPNs). It is the VPN's job to perform the security carrier's role and securely protect its payload. By using tunneling protocols (the briefcase), it can provide a secure transport of its contents from origin to destination.

By definition, a VPN is merely a secure connection between two or more networks across a public infrastructure. By taking advantage of the Internet as an access method, corporations can securely connect their users and remote locations over widely available communications. To enforce privacy, VPNs employ tunneling protocols to provide a protective barrier around the original data before sending it across an unsafe infrastructure.

Prior to modern VPNs, corporations wishing to securely connect their networks together had to lease circuits from providers. The installations of these circuits were timely and expensive in comparison to modern VPNs. Not to mention, the installed leased lines were fixed and could not be changed without requiring an overhaul of the network. As the company expanded, the inconvenient process would need to repeat for each location. In addition, mobile users requiring connectivity to the central office were required to use slow analog modems and dial into an access server while incurring long distance charges. The solution to all of these downfalls is to make the connection virtual and utilize the Internet as an infrastructure. This modern connectivity is far more scalable and significantly cheaper than traditional VPNs utilizing leased lines.

It must be said that the term "secure" is used relatively throughout this entire book. VPNs provide additional security when traversing the Internet; however, no solution is totally secure. Even the toughest security carriers can be compromised if the attacker is resourceful enough.