Today I am going to be introducing the popular network scanning tool, Nmap.
Nmap allows one to 'map' an entire network by scanning ports (both TCP & UDP), performing operating system detection, ping sweeps and more.
This allows for a network administrator to determine the relative security of their lan; by detecting the state of all ports on a specific target. Nmap will even give hints as to what certain ports are primarily used for.
Here is a sample input and what to expect as an output:
nmap -sS -vv 192.168.0.0/24
This command will perform a TCP SYN (-sS) scan of the entire 192.168.0 network, with two levels of verbosity. (-vv)
As a result the administrator would know which TCP ports are open on all hosts, and the services associate with said port. This is just a small sample of the power of Nmap, which like all network tools, should be used for the purposes of good, not evil.
-Chris
