The Key Module Of New-type Distributed Firewall System

Distributed firewall is a new-type firewall system structure. It keeps a lot of advantages while overcoming a lot of shortcomings of the firewall of the tradition. The purpose of this paper is to study, design and realize the function of firewall and IDS module of Windows host computer. This module and policy server, log server and network firewall together forms completed distributed safe defense system -the distributed firewall. First of all, this paper states relevant technological foundations, discuss and analyze technology of host firewall, IDS technology and packet filter technology of windows operating system deeply, and analyze the pluses and minuses of different interception technology. Secondly, it is discussed the basic principle, essential characteristic, ensemble architecture and modules of the distributed firewall system. Discussing overall design plan of host firewall module, concrete implementation method and technology used. Decide that using SPI plus NDIS implement network packet intercept. Divide this system to three modules: SPI filter, NDIS filter, policy receiver. And define the interface of each other. The main data structure is declared also. And then, discusesing the implementation method of host IDS and IDS interactive with the host firewall technology. Finally, there are test result and analysis of performance, and looked forward to the expansion and development in the future on the existing foundation.