If you wish to identify the software Version (-sV flag) of services running on machine’s open ports, just provide the -sV flag to nmap.
Type the command:
nmap -sV x.x.x.x
where x.x.x.x is the ip address that you wish to scan.
You will get an answer similar to this:
Starting Nmap 5.21 ( http://nmap.org ) at 2011-12-22 22:47 EET
Nmap scan report for x.x.x.x
Host is up (0.00024s latency).
Not shown: 997 closed ports
PORT STATE SERVICE VERSION
80/tcp open http Apache httpd 2.2.20 ((Ubuntu))
443/tcp open ssl/https?
902/tcp open ssl/vmware-auth VMware Authentication Daemon 1.10 (Uses VNC, SOAP)
1 service unrecognized despite returning data. If you know the service/version, please submit the following fingerprint at http://www.insecure.org/cgi-bin/servicefp-submit.cgi :
SF-Port443-TCP:V=5.21%T…… blah blah blah…
Service detection performed. Please report any incorrect results at http://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 95.18 seconds