I began to have some problems using ZoneAlarm on Windows Vista. It often blocked all the internet traffic, if I ran a bittorrent client (like uTorrent or Vuze). The only solution was the restart. The problem seems was caused by a service, Microsoft Adapter 6to4, which incapsulates IPv6 into IPv4 (used by torrent), that doesn’t run correctly with ZoneAlarm, and crashed the connection with my pc.
So I must use another firewall, what a pity, ZoneAlarm it’s (was) my favourite.

If you want more information about, read Microsoft forums, or Configuring and Deploying IPv6 on Windows Vista.

I realized also that ZoneAlarm cause another problem: it avoids killing processes. If you are using ZoneAlarm under Windows Vista (I don’t know if also with Xp) and you go to Task Manager to kill process (not the applcation, but the really the process), it makes it impossible, the process still lives. Without ZA, the problem goes away.