As workforces get more and more decentralized and telecommuting becomes more widespread, businesses of all sizes have come to depend on virtual private networks, or VPNs. A VPN is a secure, private network that runs on a public network (usually the Internet). VPNs can allow remote workers secure access to your network, just as if they were at their desks in your office. If you or your employees are routinely away from your office and need access to your company's network, a VPN is an inexpensive way to increase productivity — without sacrificing security.
The name "virtual private network" gives you a clue about how VPNs actually work. VPN software programs "carve out" a section of the Web, and allow only authorized users to access it. This virtual network runs on top of an existing network and is private. Hence the name.
Users who provide the correct login information are granted access to the VPN gateway at the office. Once they're connected though the gateway, they can access the network just as if they were at their desks — reading and sending e-mail, opening and storing files, or working on specific local applications.
To create a secure link between a mobile user and the network, you need a VPN client and a VPN gateway. The VPN client is a software application that's installed on the mobile computer of the remote user, and the gateway is a program or computer on the network end that lets in authorized users and keeps out unauthorized ones.
To provide additional security, the client encrypts data before it sends it out, and the gateway decodes it once it arrives. This communication between client and gateway is known as tunneling.
Even a one-person company can reap the benefits of VPN technology. Both Windows Server and Windows XP have built-in VPN capability, so if your LAN runs on Windows Server, it's just a matter of enabling and configuring the VPN features. That's easier said than done, but you don't have to be a computer science major to do it, either.
Of course, there are many non-Microsoft alternatives, too — many designed for the home PC user. Many firewall applications also come with VPN capability, as a VPN gateway is very similar to a firewall. Both let trusted traffic in and keep intruders out.