[root@node18 opt]# nmap -bash: nmap: command not found [root@node18 opt]# yum install -y nmap ... [root@node18 opt]# nmap -sT -p3389 218.206.112.0/24 Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2012-10-26 15:36 CST Interesting ports on 218.206.112.1: PORT     STATE  SERVICE 3389/tcp closed ms-term-serv Interesting ports on 218.206.112.11: PORT     STATE    SERVICE 3389/tcp filtered ms-term-serv ... [root@node18 opt]# nmap -sT -p3389 218.206.112.0/24 | grep -B2 open Interesting ports on 218.206.112.100: PORT     STATE SERVICE 3389/tcp open  ms-term-serv -- Interesting ports on 218.206.112.132: PORT     STATE SERVICE 3389/tcp open  ms-term-serv [root@node18 opt]#