Xtables-Addons On Centos 6 & Iptables GeoIP Filtering
This tutorial will explain how to install aditional modules for the kernel to use with iptables rules sets (netfilter modules). Xtables-addons is the successor to patch-o-matic(-ng). Likewise, it contains extensions that were not, or are not yet, accepted in the main kernel/iptables packages. Xtables-addons is different from patch-o-matic in that you do not have to patch or recompile the kernel.
Read more: http://www.howtoforge.com/xtables-addons-on-centos-6-and-iptables-geoip-filtering