Using a Windows XP system in its default setup on the Internet "amounts to a car parked in a bad part of town, with the doors unlocked, the key in the ignition and a Post-It note on the dashboard saying, `Please don't steal this'," according to a recent article in the Washington Post.

In the article, the newspaper reports that Windows is "insecure by design" because the XP Home Edition ships with five ports open to the Internet. By way of comparison Mac OS X ships with none open, and Red Hat Linux ships with its firewall turned on.

On a personal computer "ports" are software channels open to the Internet or to a network reserved for specific tasks, such as publishing a Web page.

Hackers can use open ports to gain unauthorised access to a system or network. Viruses, once installed in a host system, can exploit open ports to spread to other computers.

According to Symantec (www.symantec.com/mac/security/protect.html) hackers find open ports to exploit by sending probes or "pings" out over the Internet, checking computers for open ones they can break into.

Once an open port is found, a hacker can break into your computer and access everything you keep on your hard drive, including any personal information or wreak havoc by destroying files. They can also take over your computer by planting what is called a "Trojan Horse", a virus sent by an e-mail that once opened can be used to create a "back door" in your computer that allows hackers access to your system.

One of the most notorious of these, "back orifice", allowed a hacker to see every keystroke and password entered on an infected system.

How do you find out if your system is vulnerable? First, subject your system to an online check provided by Symantec at http://securityresponse.symantec.com. Click on "Check for Security Risks".

Under the "Hacker Exposure Check" section I can report that all my ports were operating in the "stealth" mode meaning that my computer doesn't respond to port probes and is virtually invisible to hackers scanning the Internet for potential targets. The reason?

I use a free firewall program (ZoneAlarm) to control access into and out of my computer. And of course, I have an anti-virus program installed on my computer.

These are the basic tools in the fight to keep your system safe. At the Symantec site you can also complete a free online virus check of your computer to see whether it is infected. If you have lots of files, the process can take a lot of time, but it is worth the trouble. You can also take the Digital Defense Test, provided by Cnet and ZDNet at http://techupdate.zdnet.com.

The actual URL is too complicated to be printed in full here. Just do a search for "Digital Defense Test" in the space provided. The package consists of a series of Webcasts discussing security issues businesses face.

Online surveys for business and individual users feature study guides and tutorials to help focus on the issues involved. It' s heavy going but the package brings together a lot of issues in one spot.

Tech Tattle deals with issues in technology. Contact Ahmed at editoroffshoreon.com