NMAP – Network exploration tool and security / port scanner v4.0 released

Nmap aka Network Mapper is an open source tool for network exploration
and security auditing. It was designed to rapidly scan large networks, although it works fine against single hosts. Nmap uses raw IP packets in novel ways to determine what hosts are available on the network, what services (application name and version) those hosts are offering, what operating systems (and OS versions) they are running, what type of packet filters/firewalls are in use, and dozens of other characteristics. You can download it here and read more info here. Happy hacking with Nmap ;)