Research And Implementation Of Intelligence Content Filtering Firewall Based On Linux

The computer network already became one of important method for obtaining information in daily life. The abundant information took convenience for everybody. It has become the new security threat in the meantime. The spam increased unceasingly;the bad content about violence and pornography were contained in the web more and more;the event of divulging a secret occurs frequently through the instant message;the virus invasions are more and more serious. Content security problem became prominent day by day. Therefore it has the great significance that researching the network content security and developing content product.The traditional firewall played the extremely vital role in the network security, but it cannot be withstand the threat from the Internet content security. This paper studied the insufficiency of traditional firewall. According to intelligent firewall developing trend, this paper proposed a content filtering firewall model and implemented a content filtering system. It has many functions, including monitoring and filtering. The system has highly effective and good accuracy. The research work and the contribution can be summarized in the following aspects:(1) Researching the firewall developing process, discussing the advantage and trend of intelligent firewall. As well as, analyzing the idea and implement of Netfilter security framework. Discussing the existing content filtering technologies, as well as expatiating mechanism based on the Netfilter frame.(2) An intelligent content Filtering firewall model has been proposed in this paper. It based on Netfilter frame on the Linux platform. The existing filtering technology has laid the reasonable position, in order to implementing the filtering about spam, bad web page, and instant message. It decreases the judgment complexity and enhanced the filter efficiency by delaying the time-consuming computing.(3) In order to validate previous model, an intelligent content Filtering system base on Netfilter frame has been designed and implemented. The application layer SMTP protocol, POP3 protocol, and HTTP protocol, UDP protocol has been expanded on the Netfilter frame. The system has friendly interactive interface, and also has provided the monitoring function.(4) The key technologies of the system realization has been expatiate include the vector space model, the method of Baye classifies, communications between kernel space and user space, Chinese segmentation, the text indicated, term selection, session tracking and reverting to original state,and so on.It was proven by experiment that the providing system model has good structure, and it was expand easily. The Intelligent content Filtering firewall system designed and implemented by this paper has friendly interactive interface, good effect and performance. This system research will helpful to develop the content security product. Furthermore, it would safeguard the content security in the local area network effectively.