The Research Of The Way To Block The Illegal Access Network Using NAT Gateway Based On NDIS

In recent years, with the rapid development of computer network, resulting in rapidincrease in the number of people using the computer network. IP address the shortage ofphenomenon is more and more obvious, which makes the increasingly common of usingNAT. And along with the computer application technology rise to build NAT more easily,which makes the terminal private access to the NAT increasingly common phenomenon.This phenomenon not only has increased the difficulty of network management, but alsoaffect the legitimate interests of network operators. Although there are many methods ofdetection of the NAT, but there were many defects and are not well prevent the use of NAT.This paper discusses the content, and puts forward NDIS Intermediate layer technology toblock the illegal using of NAT gateway.This paper first introduces the research content and objectives, analysis of severalcommon packet interception technology in the Windows system, the selected NDISIntermediate layer technology of choice in this article, Finally, blocking the NAT programdesign and implementation. Using the features of NDIS intermediate layer technology cancapture all through the network card packet, and then copy these packets into the bufferqueue. When need to deal with these packets, removed from the buffer queue, put thesepackets into the filter rules. If these packets conform to the rules, referred to the furtherprocessing, else directly discarded. The application control the NDIS intermediate driver,the application communicate with the NDIS intermediate driver using the interface thatprovided by the NDIS intermediate driver. The application of the main function is to controland monitoring of the driver.Finally, the paper does the test of the drive and the application program. The resultshows that the system can prevent the use of the NAT gateway efficiently and has feweffects on the equipment.