hadi motamedi wrote: > Dear All > To open a port , I know that I need to go to "System -> Administration > -> Security Level and Firewall" -> Other ports and then I can open > port-5901 as tcp protocol . Can you please do me favor and let me know > how it can be done from the command line (if my CentOS is text-mode > installed) ? (perhaps via iptables?) older versions of RHEL had a lokkit text menu based util for setting basic firewall ports. I dunno but it may still be available in current versions. all it actually does is edit that sysconfig/iptables file and restart the iptables service that tony mentions, same as the GUI program does. also, you could make a backup of that file on a GUI system, add a port, then diff the backup and the current iptables file to see exactly what the GUI does