BlackICE Defender and McAfee.com Personal Firewall have the best configuration options and default settings.

CNN: Insulate your PC from hackers

Cluley says a personal firewall should be installed by home broadband users.

CNN: Sasser worm rips through Internet

"Overcautious customers tend to disable Poproxy manually in the Task Manager (accessed by hitting Control-Alt-Delete in Windows), others get weary of the program and decide to block it when their personal firewall reports that Poproxy is trying to connect to the Internet, " said Van der Grift.

CNN: Norton AntiVirus puts a lock on e-mail