Gary Kuhlmann - March 11, 2014
In addition to using system-config-firewall (which is not installed on RHEL by default) one can edit the configuration file directly. This also helps if you need to add more specific rules.
Open a port up to everybody:
-A INPUT -m state --state NEW -m tcp -p tcp --dport [Port Number] -j ACCEPT
Open a port up to specific ip address:
-A INPUT -s [IP ADDRESS or Range] -m state --state NEW -p tcp --dport [Port Number] -j ACCEPT
After editing the file just restart iptables using:
service iptables restartSource: http://fedoraproject.org/wiki/How_to_edit_iptables_rules