Windows XP Power Hound

Firewalls

No doubt you've heard about all the evils that lurk online: viruses that wipe out data on your computer, hackers that break into your system, or spyware that surreptitiously tracks what you type. It's enough to make you consider unplugging from the global network and settling for Solitaire on your PC.

A better option is to employ a firewall—a valuable piece of software that guards your computer when you're online. Essentially, firewalls erect a barrier around you while you surf the Internet, blocking malicious intruders from gaining access to your PC. Here are some hints on how to use firewalls—both the one built into Windows XP and a sophisticated version you can download.

A Basic Firewall

For basic PC protection when you're on the Internet, turn on XP's built-in Internet Connection Firewall (ICF). ICF provides nuts-and-bolts security by stopping any inbound Internet traffic you didn't request. In other words, if you want to visit a Web site, check email, or download a file, the firewall lets that data through; but if a hacker tries to sneak onto your system, the firewall makes like J-Lo's personal bodyguard and blocks the way.

Be forewarned that ICF has one very serious drawback: It doesn't protect you against Trojans , which are programs that let someone else take control of your PC. Using a Trojan, a hacker could copy your files or use your PC to launch attacks against other computers. (XP's built-in firewall can't stop Trojans since it only blocks incoming Internet ...