目录 一、防火墙的概念与构成
二、筛选路由器（Screening Router）
三、防火墙的不足与探索
四、结束语
五、参考文献： 参考资料 1.[美]Joseph L. Weber著 卜照斌，段来盛等译。JAVA2编程详解[M]。电子工业出版社
2.Marcus Goncalves著。宋书民，朱智强等译。防火墙技术指南[M]。机械工业出版社
3.锐思创作室编著.Jbuilder3环境下的JAVA编程[M]。人民邮电出版社
4.[美]Borland公司著，魏伟，陈维军等译。Jbuilder开发人员指南 机械出版社
5.金勇华，曲俊生等。JAVA网络高级编程。人民邮电出版社
6.梅杰，许榕生。Internet防火墙技术新发展。微电脑世界 .
7.Ranum M J. Thinking About Firewalls.
http//www.securedsystems.com/links.htm
8.Frederic J. Cooper, et al. Implementing Internet Security. New Riders Publishing .1995.
9.Raig Hunt. TCP\IP Network Administration. O’Reilly

随着计算机的飞速发展以及网络技术的普遍应用，随着信息时代的来临，信息作为一种重要的资源正得到了人们的重视与应用。因特网是一个发展非常活跃的领域，可能会受到黑客的非法攻击，所以在任何情况下，对于各种事故，无意或有意的破坏，保护数据及其传送、处理都是非常必要的。计划如何保护你的局域网免受因特网攻击带来的危害时，首先要考虑的是防火墙。防火墙的核心思想是在不安全的网际网环境中构造一个相对安全的子网环境。本文介绍了防火墙技术的基本概念和系统结构，讨论了实现防火墙的两种技术手段：一种是基于分组过滤技术（Packet filtering），它的代表是在筛选路由器上实现的防火墙功能；一种是基于代理技术（Proxy），它的代表是在筛选路由器上实现的防火墙功能. 关键词：网络 安全 防火墙 Abstract: Along with the fast computer development and the universal application of the network technology, along with information times coming up on, Information is attracting the world’s attention and employed as a kind of important resources. Internet is a very actively developed field. Because it may be illegally attacked by hackers, It is very necessary for data’s protection, delivery and protection against various accidents, intentional or want destroy under any condition. Firewall is the first consideration when plan how to protect your local area network against endangers brought by Internet attack. The core content of firewall technology is to construct a relatively safe environment of subnet in the not-so-safe network environment. This paper introduces the basic conception and system structure of fire-wall technology and also discusses two main technology means to realize fire-wall: One is based on packet filtering, which is to realize fire-wall function through Screening Router; and the other is Proxy and the typical representation is the gateway on application level.....