When selecting a personal firewall, you should consider whether you want one that controls outbound communication with the Internet. The advantage is that you are alerted the first time any program tries to call out and you are given the option of deciding whether to allow it one time, always or never. The disadvantage is that you may have no idea what the program trying to call out is or what it does.

To be effective, outbound control requires a user who has need or interest and skill or knowledge. For the last year or two, this was fine because "early adopters" by definition love new stuff. Many alerts do not say that [program name] is trying to call home; instead, they often give a file name like [xyzabc.doit]. Everyone (the rest of us) who uses the Internet knows, of course, what "xyzabc.doit" means (right?). So, outbound control is a great feature but it requires ongoing effort on your part to use it effectively. New releases of Norton, ZoneAlarm and other firewall products make it easier to set up outbound communication rules and understand what is going on.

This issue effects the way reviewers rate personal firewall software and explains, in part, why the same product may be rated highly by one reviewer and lower by another. If you are concerned about controlling unauthorized outbound traffic, take a look at the Personal Firewall Scoreboard, Steve Gibson, LeakTest (scores to be updated as new versions are released). For information on how to detect, remove and repair damage caused by Trojan horses and worms (which are often the malware trying to call out that you may want to control), see our Anti-Trojan page.

Below is a link to a comprehensive list of independent third-party reviews of twenty-four personal firewall products for Windows. In addition to a personal firewall, you should have Anti-Virus, Anti-Trojan and privacy software to make your computer 99% hacker proof.