P2P programs, although very useful and fun, can also be dangerous for your computer. PeerGuardian is a great application that operates as a security guard for your PC, controlling unauthorized access of users connected to P2P networks. PeerGuardian works by blocking and saving to a log file all connection attempts over TCP or IP using IP address ranges and a black list of unauthorized users. It supports all the popular P2P file sharing applications like KaZaA, iMesh, eMule, Ares and more. And it is automatically updated by adding new blocked IPs to the black list. This tool is very easy to use and it’s free too.