$ nmap localhost
Starting Nmap 5.00 ( http://nmap.org ) at 2012-03-27 23:56 JST
Warning: Hostname localhost resolves to 2 IPs. Using 127.0.0.1.
Interesting ports on localhost (127.0.0.1):
Not shown: 999 closed ports
PORT STATE SERVICE
631/tcp open ipp
Nmap done: 1 IP address (1 host up) scanned in 0.69 seconds
$ nmap localhost
Starting Nmap 5.00 ( http://nmap.org ) at 2012-03-27 23:56 JST
Warning: Hostname localhost resolves to 2 IPs. Using 127.0.0.1.
Interesting ports on localhost (127.0.0.1):
Not shown: 999 closed ports
PORT STATE SERVICE
631/tcp open ipp
Nmap done: 1 IP address (1 host up) scanned in 0.69 seconds