Design And Implementation Of Network Behavior Monitoring System

The prosperous development of the Iternet brings more and more impact to ourlife,work and study,giving great convenience to us.But at the same time, it also raisesmany issues:the hackers furiously intrude many kinds of hosts;more and more kindsof viruses spread and bring great harm;illegal information violating the laws and thesandpoint of the Party and the government can be seen everywhere. Most of currentnetwork monitor systems are based on network layer and transport layer,so it,s unableto detect and control illegal information carried in application layer.it,s important tostudy and develop application layer based network monitor and control system.Firstly this thesis points out that developing Network Content Monitor System isvery urgent;then home anatomy TCP/IP protocol involved during the thedevelopment.Based on these,linking our research objectives,we design reasonablesystem structure and provided key technologies used during system realization.It moreeffectively realized data packet capture engine by LIBPCAP based on BPF , constructlogical HASH function,and restablish TCP control block by HASH arithmetic,whichincrease the tracking efficiency of IP data packet.Furthermore it realize IP data packetrecombination algorithm and application layer data revivification of HTTP,FTP,SMTP etal;At last organized multiple keywords data structure of digital search trees,by improving text retrieval algorithm,thus improved algorithm speed and realize fulltext retrieval algorithm.