防火墙是网络安全研究的一个重要内容。该文通过对Linux数据包过滤系统——Netfilter/Iptables的研究和分析,最后利用实例讲解了利用netfilter框架编程实现新功能,这种分析有利于研究人员去开发新的好的功能,用防火墙去努力保障网络和主机的安全。 Firewall is an important part of network security research. This article through the Linux packet filtering system - Netfilter / Iptables research and analysis, and finally examples using examples explained using the netfilter framework for programming new features, this analysis is conducive to researchers to develop new good features, with a firewall to go Strive to secure the network and host.