A few weeks ago we reviewed the Sharp Zaurus handheld, a fine piece of engineering that Sharp finally remembered we had and wanted back. Darn.

Anyway, in that column we mentioned a piece of remote control software called Virtual Network Computing (VNC) created by the unlikely combination of AT&T Laboratories and the University of Cambridge.

VNC is a remote control system that lets you see the monitor display of a remote computer and makes your keyboard and mouse act as the remote computer's keyboard and mouse.

The authors note that VNC is different from other remote control solutions in that: "It is fully cross-platform [note that there is no Mac support yet - Gearhead]. A desktop running on a Linux machine might be displayed on a Windows PC, on a Solaris machine, or on any number of other architectures. There is a Java viewer so that any desktop can be viewed with any Java-capable browser. There is a Windows server, allowing you to view the desktop of a remote Windows machine on any of these platforms using exactly the same viewer. The simplicity of the protocol makes it easy to port to new platforms, and other people have therefore ported VNC to a huge variety of platforms."

They also say it "is small and simple. The Windows viewer, for example, is about 150K in size and can be run directly from a floppy. The entire Java viewer is substantially less than 100K and takes less time to download than the images on some Web pages."

Finally, the company announces that VNC "is free! You can download it (www.realvnc.com/download.html), use it, and redistribute it under the terms of the GNU General Public License." You also can get the full source code, and there's in-depth how-it-works information at www.realvnc.com/howitworks.html, including a discussion of the underlying protocol.

VNC is a remarkable package. It literally takes minutes to install, it is robust and it is fast. The machine to be monitored is the server and the remote viewer is the client. But there are some important considerations if you're going to use it. First, it's not really secure (although compared with telnet access, VNC is more like Fort Knox).

To route VNC connections through a firewall you'll have to set up your firewall to allow connections to the VNC ports. VNC can support many servers on a machine so a VNC server will accept connections on port 5900+N, where N is the server's number.