Netfilter-based Filtering Of Application Protocols

The continuous development of computer network has seen more and more application protocols be introduced, These protocols make it easy for people to obtain information, but they may cause inconvenience in certain circumstances. For example, although BT enables efficient download, network bandwidth will be used up quickly if many people use BT download simultaneously, which results in network service degrade. Therefore, it is important to identify these protocols and filtering them.Furthermore, identifying and filtering HTTP is not enough in many cases, because also it may contain garbage and even harmful information alongside useful one. There is a demand for content-based web information filtering.This paper presents an effective, commonly filtering model which is based on Netfilter provided in Linux. It can identify and filter the application protocols. In addition, the proposed model provides URL, title and keyword-based web information filtering. It can be set up on a Linux-based workstation without recompilation of the Linux kernel, as well as on a Linux-based server.