Design Of The Embedded Web Filter

In recent years the rapid development of the Internet is bringing a lot of convenience for us modern people. We can use the Internet to work, study, communicate and entertain ourselves. With a lot of useful information helping people, at the same time, many bad information also gives people a negative impact. In order to purify and protect the Internet, make its development more healthy and make its services more effective, many Internet technologies emerged, web filtering technology is one of them.The current basic protocol of the Internet network interconnection is the TCP/IP protocol. It is the protocols group of TCP (Transmission Control Protocol) protocol, IP (Internet Protocol) protocol, UDP (User Datagram Protocol), ICMP (Internet Control Message Protocol) protocol and a number of other protocols. The basic of web filtering is network data packets filtering, including capture, analysis, reconstructed and resend of the network packets.After the capture and analysis of the network packets which contain web information, according to the source IP address and web content, some network packets which do not meet the requirements will be filtered out selectively. Then we can achieve the purpose of filtering out undesirable web pages. The analysis of network packets will potentially destroy the original structure of these packets that meet our requirements, so it is indispensable to constuct and resend these network packets.The development of the embedded technology has brought people more and more convenience, the web filter designed in this paper is to be applied in embedded system. Using Ubuntu 9.10 operation system on PC and building embedded Linux operation system on target board of ARM S3C2440. Applications that have cross-compiled successfully will run on PC first and then run on ARM.