PeerBlock is an IPBlocker that lets you control who your computer can communicate with on the internet. You can block communications with advertising or spyware-oriented servers, computers monitoring your p2p activities, computers which have been "hacked", even entire countries! PeerBlock is the successor to PeerGuardian (the original IPBlocker).To give you an idea of just how powerful PeerBlock is, my PeerBlock is configured to block Hijacked, Hacked and P2P IP's and in total 911,675,868 IP's are blocked for me!

PeerBlock is freeware and compatible with Windows 2000, XP, Vista and 7 (32-bit and 64-bit).