AntiARP firewall is a very useful tool, simple but functional. even though it has very few features they are powerful and effective. AntiARP's intercepts intruder's attacks, viruses, etc. monitors IP conflicts and fix them. analyses packets and it has a virus cleaner with a well prepared database. It also tracks the attacker and automatically sets the defense.
the new version AntiARP's 5.0.1 counts with new database updates. This is a 10 day trial but the price is really cheap and it's worth it. If your are looking for a functional, simple and effective firewall with not that many features this will be perfect for you.