[ Thanks to Doug
Vitale for this link. ]
“Nmap is the de facto industry standard network scanner. It can
be installed on a variety of operating systems such as Windows,
Mac, and Linux, and it can be used via a command line interface or
with a graphical interface (the interface itself is known as
Zenmap).“Why is Nmap so popular? Because it?s fast, free, open source,
and very capable as it can perform not just ping sweeps, but port
scanning, service identification, and operating system detection as
well. Furthermore the various types of scans it performs are highly
configurable.”