First of all you do not need to recompile your kernel in redhat 7.1 to use iptables by default on a normal install 7.1 will load ipchains and iptables the only thing is ipchains will over-rule iptables on boot because you can't run them both at the same time
shutdown ipchains by doing chkconfig --level 0123456 ipchains off
service ipchains stop
then do a chkconfig --level 235 iptables on
and reboot your system to remove the ipchains.o module and load the appropriate iptables module
then go here to read and learn about setting up your iptables to meet your needs.
I hope this helps