，本书通过探讨组成因特网所有组成部分以及使得因特网不安全的各种因素，使你的专业水平更上一层楼；它详细描述和讨论了应用在因特网上的所有协议、标准和应用程序编程接口（API）以及从加密到防火墙的安全机制。本书后一部分包括市场上主要防火墙产品、工具包及应用软件的综合评述和一些防火墙的演示版和评价书-, This book by exploring the composition of all components of the Internet and make the Internet a variety of factors of insecurity, so that you are a higher level of professional standards　its detailed descr iption and discussion of the application on the Internet all the agreements, standards and applications Programming Interface (API), as well as encryption to the firewall from the security mechanism. The latter part of the book market, the main firewall, including products, tools and application software packages are reviewed and some of the demo version of the firewall and evaluation of the book