ZoneAlarm is a great firewall for the average user but if you are paranoid i would go for a hardware firewall, ZA has a few vulnerabilities one of which is: If the computer is running 256Mb of RAM or less ZA will keel over and die if there is a large scale attack involving 1000 ports or so. Other than this it is great , I use it on 4 of my boxes along with a Great hardware package.