Following are the commands to open tcp or udp ports on the server.
Before using commands for opening the port please make sure the specific port is already opened.
you can verify the port with
netstat -nap | grep : <port no>
1.you can open TCp port with
iptables -A INPUT -p tcp –dport <port no> -j ACCEPT
2. You can open UDP port with
iptables -A INPUT -p udp –sport <port no> -j ACCEPT
3 service iptables save
and for flushhing iptables use