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).
