Fedora

Here is list of all functions which should firewall backend provide

Basic

what	where
Enable/disable firewall	/sbin/service iptables & ip6tables
Enable/disable firewall service	/sbin/chkconfig
Set which port is blocked	/etc/sysconfig/ip(6)tables
Set trusted interfaces	/etc/sysconfig/ip(6)tables
Set masquerading	/etc/sysconfig/ip(6)tables
Set port forwarding	/etc/sysconfig/ip(6)tables

Please comment
If you don't agree with proposed functionality or have something to add, share it with us in Talk:SystemConfig/firewall/backend