摘要： 介绍了Linux内核防火墙的发展，对2.4.x内核中的Netfilter框架的流程和IPv4协议栈中Netfilter的实现进行了分析，通过一个内核防火墙模块实例介绍了基于Netfilter框架下的内核防火墙设计方法，对Netfilter框架下的防火墙高级功能扩展进行了展望。

关键词: 防火墙, Linux, Netfilter, 内核模块

Abstract: This paper firstly introduces the history of Linux kernel firewall. With the analysis of Netfilter framework and its implementation in IPv4 protocol stack, a simple kernel filter module is presented to illustrate the kernel firewall design technique under Netfilter framework. Finally, new directions in firewall design under Netfilter framework are briefly discussed.

中图分类号: 

• TP393.08