On Fedora Core, the iptables rules are stored in /etc/sysconfig/iptables. To change the rules, the iptables(8) utility is used. When done, store the updated rules in /etc/sysconfig/iptables by running the following as root:
# /sbin/iptables-save > /etc/sysconfig/iptables
I'm sure I'll need this again, and I'm sure I'll have forgotten all of it by then.