【摘要】 主要介绍防火墙的有关技术，对各类防火墙进行了比较，给出了一个基于Ｌｉｎｕｘ的防火墙系统ＮｅｔＧｕａｒｄ的设计与实现，重点介绍ＮｅｔＧｕａｒｄ在选型和设计方面的新颖思路。更多还原

【Abstract】 This paper introduces the firewall technology and gives the comparison of various firewalls. It also gives the design and implementation of NetGuard firewall system based on Linux, and point out emphatically the new ideas in the model select and design for NetGuard.更多还原