There are many popular firewalls like ZoneAlarm and Comodo. I have tried both and they performed quite well. Although I faced some glitches and some of the applications got stuck with them, until one day I discovered one more free firewall software that works like a charm and out beats it's popular rivals. Filseclab Firewall
Filseclab firewall is a free and extremely advanced firewall. I have tested it on Windows XP and Windows 2000 Professional and it performed well on both systems. The interface is stunning and very easy to use. 
FilsecLab Features
1. Can block the most attacks from worms, viruses and trojans.
2. Can also block some main Adware and Spyware.
3. It supports live update.
3. Double filter system for double-layer protection.
4. Digital signature verification to trust the well-known program.
5. Built-in 7 operational modes.
6. Advanced real time network monitor.
7. Interactive rules creator to define new rules.
8. Password protection for rules and configurations.
9. It is very easy to backup and restore the rules.
10. Two log file types, ascii and binary, can be easily exported.
11. Supports live update for rule-definition, traffic graph, privacy protection, Windows Security Center, balloon message alert and much more.
You can turn off selective features to fine tune it according to your needs. It can co-exist with your existing anti-virus system and does not hinders its operation.
Free Updates by Email Free updates by RSS (What is RSS?)
