My previous articles have been written about VPN theory - the various technologies that underpin Virtual Private Networks. This article is devoted to VPN practice. But first, a brief recap for the late arrivals among you: virtual private networking is a means of creating a secure connection, over the public Internet, between your computer and a gateway or server located elsewhere, such as another office. A VPN connection is secure in two ways, firstly when establishing a connection you or your computer must be authenticated. Then, once the connection is established all traffic between your computer and the gateway/server is encrypted for privacy.
One common use for a VPN is to allow users access to a network from outside a firewall. If your office network has a firewall, a VPN server running inside it could permit you to connect to the network from outside - say, over a broadband cable connection from home - and access resources as if you were connected locally.
A VPN server is a piece of hardware or software that can act as a gateway into a whole network or a single computer. It is generally always-on and listening for VPN clients to connect to it.
The other side
Actual VPN server software is rather rare. But Windows Server-level operating systems such as Windows 2000 Server, Windows Server 2003 and Small Business Server 2003 have VPN server software as standard, as does Windows XP.
However, VPN server software is not strictly essential, it's possible to throw up a tunnel directly between routers. So a VPN client can be hardware, too. A client initiates a call to the server and logs on. Then the client PC and server can communicate. They are on the same virtual network. Many broadband routers can pass one or more VPN sessions from your network to the Web.
The VPN client connection
Here's how to create a Windows XP VPN connection to a server. Firstly open Control Panel and choose Network Connections, then start the New Connection Wizard by clicking on Create a new connection. Select "Connect to the network at my workplace" and click Next. Click on Virtual Private Network connection and click Next. Give the connection a name and click Next.
If prompted, select whether or not you have to dial to the Internet before establishing a VPN connection - you may need to, if you have a USB broadband modem rather than an ADSL router. Next, enter in the IP address of the server you want to connect to. Finally, check whether you want to have an icon placed on the desktop and click on the Finish button. And that's it - I told you it wasn't hard!