A robust and open source security tool for network discovery and security auditing.
Nmap ("Network Mapper") uses raw IP packets in 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.
Nmap runs on all major computer operating systems, with official binary packages available for Linux, Windows, and Mac OS X, and works equally well in both large network and single-host environments.
In addition to the classic command-line Nmap executable, the Nmap suite includes an advanced GUI and results viewer (Zenmap), a flexible data transfer, redirection, and debugging tool that also offers transfer encryption (Ncat), a utility for comparing scan results (Ndiff), and a packet generation and response analysis tool (Nping).
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