Iptables 指南 1.1.19
http://man.lupaworld.com/content/network/iptables-tutorial-cn-1.1.19.html
Linux数据包路由原理、Iptables/netfilter入门学习
http://itindex.net/detail/49448-linux-%E6%95%B0%E6%8D%AE%E5%8C%85-%E8%B7%AF%E7%94%B1
Iptables入门教程
http://drops.wooyun.org/tips/1424
linux防火墙iptables常用规则
http://www.xker.com/page/e2012/0926/120758.html
NAT – Network Address Translation
http://www.karlrupp.net/en/computer/nat_tutorial