Network exploration tool and security scanner
Nmap is a utility for network exploration or security auditing. It supports ping scanning (determine which hosts are up), many port scanning techniques (determine what services the hosts are offering), and TCP/IP fingerprinting (remote host operating system identification). Nmap also offers flexible target and port specification, decoy scanning, determination of TCP sequence predictability characteristics, reverse-identd scanning, and more. In addition to the classic command-line nmap executable, the Nmap suite includes a flexible data transfer, redirection, and debugging tool (netcat utility ncat), a utility for comparing scan results (ndiff), and a packet generation and response analysis tool (nping).