Do you need a personal firewall?

You have installed a legal copy of the leading antivirus software on your PC. You regularly download the latest virus signatures. Are you giving your PC enough protection?

In the past, when your PC was not connected to the Internet, when the virtual world was still free from rogues and villains, that would have been enough. The only way viruses could enter your PC was through the removable media, such as floppy diskettes.

In the past, getting rid of viruses was just as easy as typing FDISK/MBR after the DOS prompt, and it would work in most cases.

Today, PCs are connected to the Internet. A growing number of them stay connected all the time. Meanwhile, the rogues and villains have also been sharpening their weapons and heightening their targets. So the virtual world is completely different now. Even the most up-to-date antivirus is no longer adequate in shielding your systems against intrusion.

What are the purposes of these intrusions? Plenty. The rogues and villains may want to steal important information stored in your computer. If you use Internet banking, for example, they want your account numbers and passwords. If you do online shopping, they want your credit card numbers. If you have a list of the e-mail addresses of your friends and business associates, they want to steal them, too.

If they are marketing their products and services, they bombard you with pop-up screens featuring their offerings. Or, if they want to wreak havoc on the Internet, they plant small programs in your hard disk, and at a preset time, or with their trigger, these programs will use your computer to bombard identified Websites. In cases like this, traffic on the Internet becomes so heavy that the Internet becomes paralyzed.

The firewall has been around for some time. Like antivirus software, the firewall is a bunch of programs that check the packets of data that enter or leave your computer. They will detect intrusion into your computer, and will alert you to any intrusion attempt. They will stop those annoying pop-ups. They will search and destroy spyware -- those programs planted by the rogues and villains to record your keystrokes, etc.

Some more sophisticated firewall suites also have the ability to hide in your computer so that hackers will not "see" them on the Internet, to allow you to avoid certain Websites known for their hazardous materials.

A personal firewall is already included in Windows XP. To check whether it is turned on or off, click on your ISP's Network Connection icon on the applications tray on the right end of the task bar. Remember, it has to be the one that manages your connection to the Internet. Once the ISP Status window appears, click on the Properties button. On the next window, click on the Advanced tab. If the option under Internet Connection Firewall is not activated, click on it until you see the check mark in the box.

Like many other built-in functions in Windows, you may fare better if you add third-party products. There are plenty of firewall software programs available on the Internet. Some can be downloaded for free, others let you test for a limited period of time. Top products, according to reviewers, include ZoneAlarm Pro, Norton Personal Firewall 2004 and McAfee Personal Firewall Plus.

If you store a lot of confidential data on your computer, and it is connected to the Internet, adding a firewall is an investment that you must make, in addition to the legal copy of antivirus. -- Zatni Arbi