计算机网络安全与防火墙技术

Computer Network Security and Firewall Technology

防火墙技术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主要技术手段：一种是基于分组过滤技术（Packetfiltering），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），它的代表是在应用层网关上实现的防火墙功能。

The core idea of firewall technology is in an insecure Interact environment to construct a relatively safe environment for the subnet.This article describes the basic concepts of firewall technology and system architecture,discusses the firewall to achieve two main techniques：one is based on packet filtering technology （Packet filtering）,it is represented on the screening router firewall to achieve;a is based on agent technology （Proxy）,it is represented in the application layer implemented on the gateway ftrewall.