Nmap

Nmap is a network port scanner computer program. Nmap is used to detect open portss on a specified computer, and can also try to deduce what programs are using those ports, and what operating system the computer is running.

Like most tools used in computer security, Nmap is useful to both system administrators and crackerss. System administrators can use it to check computers under their authority for unauthorized servers, while crackers can use it to "scope out" a potential target.

Nmap provides a less thorough vulnerability test than Nessus, however, it is also less likely to be spotted by an intrusion detection system, and less likely to interfere with the normal operation of the computer or computers being scanned.

External links:

• The Nmap scanner