“Nmap is the premier open source port scanning tool, and
provides several powerful methods to analyze weaknesses in a TCP/IP
“Nmap is open source and falls under the GNU public license.
NMAP works with several different flavors of Unix, but is most
commonly seen running under Linux, where it has no limitations of
its features. What makes nmap such a powerful tool is its ability
to create and transmit unusual TCP/IP packets and sequences.”
“Use nmap to audit your firewall and/or Intrusion Detection
systems’ capabilities. Nmap uses many stealth scanning techniques.
By auditing your firewall logs, you can determine if it is catching
your scans, and if it is providing proper notification.”
“Determine which TCP and UDP ports are open on your host
systems. Obviously, this is what port scanning software is for. The
ability for nmap to detect open UDP ports is a differentiator
between it and other products.”