The Study Of Network Security Technology: Based On Ip Technology: Based On Ip Masquerade

This paper consists of four chapters.In the first chapter, firstly, the paper introduces four kinds of architecture of firewalls including the Packet Filter, Dual-Home Host, Screened- Host, Screened-Subnet, together with their working principle of firewall simply, as well as their merit and demerit. Then, the paper introduces several technologies on how to achieve to set up the firewall, such as packet filter, application proxy and circuit proxy, static examine and content examine. At the last, the paper discusses the research and development trends at the present from the firewall products of the entire world.The second chapter discusses the network communication structure of the Windows operating system. In the Windows operating system, data is sent from one layer to another in logic. The application program of network sends control information and data to driver protocol of network, for example TCP/IP, then the network driver protocol sends them to network interface driver protocol, lastly the network interface driver protocol operates in the network interface carddirectly. The paper also points out that the network interface card have four types of modes: Broadcast Mode, Multicast Mode, Unicast Mode, and Promiscuous Mode. At the last, the paper introduces a network development Kit梡acket32, which was developed based on network driver interface protocol by University of Canberra, Australia. Then the paper discusses the contents of the packet32, the structure of datagram and network interface card, and how to use it.The third chapter describes the concept of the IP masquerade and its working principle in the Linux operating system. The paper introduces the concept of IP masquerade, then discuss its working principle and system architecture in detail. It is point out that the IP masquerade is on the way of experiment phase, and its employ flat roof and application program for clients.The fourth chapter mainly introduces the principles and functions of the firewall, which is based on the IP masquerade knowledge. It is point out that the data communication is achieved by data packet. Then, this paper discusses the architecture of the internet, the IP packet, and the architecture of the TCP datagram. Based on the discuss as above, the paper presents a new packet-filtering firewall based on IP masquerade in Windows operating system, and explains its principles of framework, rules for filtering, and working procedure in detail. Lastly, this paper sets up a program which will achieve this goal, and gives main data architecture.