nmap  -sV -p50030,50060,50070,50075,50090,60010,60030 -Pn  namenode1.example.com namenode2.hadoop.ripe.net datanode1.hadoop.ripe.net

Starting Nmap 5.61TEST2 ( http://nmap.org ) at 2011-11-09 20:16 CET
Nmap scan report for namenode1.example.com (192.168.0.25)
Host is up (0.016s latency).
PORT      STATE  SERVICE VERSION
50030/tcp open   http    Jetty httpd 6.1.26
50060/tcp closed unknown
50070/tcp open   http    Jetty httpd 6.1.26
50075/tcp closed unknown
50090/tcp closed unknown
60010/tcp open   http    Jetty httpd 6.1.26
60030/tcp closed unknown

Nmap scan report for namenode2.example.com (192.168.0.26)
Host is up (0.013s latency).
PORT      STATE  SERVICE VERSION
50030/tcp closed unknown
50060/tcp closed unknown
50070/tcp closed unknown
50075/tcp closed unknown
50090/tcp open   http    Jetty httpd 6.1.26
60010/tcp closed unknown
60030/tcp closed unknown

Nmap scan report for datanode1.example.com (192.168.0.30)
Host is up (0.016s latency).
PORT      STATE  SERVICE VERSION
50030/tcp closed unknown
50060/tcp open   http    Jetty httpd 6.1.26
50070/tcp closed unknown
50075/tcp open   http    Jetty httpd 6.1.26
50090/tcp closed unknown
60010/tcp closed unknown
60030/tcp open   http    Jetty httpd 6.1.26