I was a bit unhappy with ZoneAlarm. It was always resetting rules I had applied. Have been using Norton FireWall on 2 systems and it has caught backdoor trojans on downloaded shareware. I also use a program called attacker. I am happy with that. You need to add additional ports that common viruses and trojans use but it works. I see alot of referance to tiny firewall and will have to try it out.