Geht ohne Probleme:

root@tomovic-Satellite-L300:/home/tomovic/Dokumente/hack# nmap 127.0.0.1

Starting Nmap 6.00 ( http://nmap.org ) at 2013-08-25 16:50 CEST
Nmap scan report for localhost (127.0.0.1)
Host is up (0.000011s latency).
Not shown: 999 closed ports
PORT    STATE SERVICE
631/tcp open  ipp

Nmap done: 1 IP address (1 host up) scanned in 0.11 seconds
root@tomovic-Satellite-L300:/home/tomovic/Dokumente/hack#
root@tomovic-Satellite-L300:/home/tomovic/Dokumente/hack# nmap 127.0.0.1

Starting Nmap 6.00 ( http://nmap.org ) at 2013-08-25 16:51 CEST
Nmap scan report for localhost (127.0.0.1)
Host is up (0.000011s latency).
Not shown: 998 closed ports
PORT    STATE SERVICE
80/tcp  open  http
631/tcp open  ipp

Nmap done: 1 IP address (1 host up) scanned in 0.11 seconds