The Design And Realization Of PC Firewall

With the rapid development of Internet, many enterprise users and single users connect to it. People enjoy the convenience and great efficiency brought by the Internet, at the same time, their computers are continually suffered from many kinds of computer virus and hackers' attack. One of the effectual and important solutions for network security is to set firewall. Now there are many firewall for enterprise, but there is few firewall for personal computer. Being based upon this situation, a firewall of personal computer working on Windows operating system is designed and implemented. Comparing the existent personal firewall, a new method which is based on Winsock Service Provider Interface (SPI) is used to realize the PC firewall. SPI is a new programming interface afforded by the Windows Sockets 2.0. With the new method, many functions can be completed, such as transfers quality control, expanding TCP/IP protocol stack, URL filtration and network security control, through inserting a layer in Socket. Because the method is realized in user mode of the operating system, the software is easy to be programmed and to be combined to windows application.Firstly, the theories of network security are introduced in the thesis, including causations, aims and categories of network security . Then the problems of network security which personal computers are confronted with are brought forward. The second, the principles and technologies of firewall are described, including the concepts, functions and various technologies of personal firewall which are the emphases. The third, the whole framework of the designed personal firewall is introduced in detail. At last, how to design and implement the involved functional modules is expatiated in the succedent chapters.