防火墙是网络安全的关键技术,其核心思想是在不安全的网络环境中构造一个相对安全的子网环境.本文重点就网络安全论述了网络防火墙安全技术的分类及其主要技术特征、防火墙的安全功能、实现防火墙的主要技术手段、防火墙技术优点和缺点、防火墙发展的新技术趋势以及防火墙部署原则,并从防火墙部署的位置详细阐述了防火墙的选择标准.并就信息交换加密技术的分类加以分析,针对PKI技术这一信息安全核心技术,论述了其安全体系的构成. -A firewall is a key network security technologies, its core idea is the network in an unsafe environment to construct a relatively safe environment subnet. This paper focuses on network security firewall on the network security technology classification and its main technical features, firewall, security function, the realization of the main technical means of the firewall, firewall technology advantages and disadvantages, firewall development of new technology trends and the deployment of the principle of a firewall from a firewall in detail the location of the deployment of firewall selection criteria. and the exchange of information, the classification of encryption technology to analyze , PKI technology for the core of the information security technology, discusses the composition of its security system.