Research And Application Of Data Packet Interception Technology Under Windows Userspace

With the rapid development of network technology, which makes great changes in people's lives and production. It riches people's spiritual life, meanwhile, it brings convenience to people's work. However, computer network is a two-edged sword. It has a diversity of connection, uneven distribution of terminal, open, interconnect, easily be attacked, and so on. As a result, Security and confidentiality of online information is critical.As the network Security issues become increasingly prominent, Network Security products attracted a great attention. Personal Fire Wall is also slowly becoming popular during this period. Because of its small and convenient feature, it stands out among many of network Security products, and also becomes the most popular favorite Security product to personal users. In the thesis, the author will discuss the development of Fire wall, the classification of Fire Wall technology, the general principles of Fire Wall, and so on. Still, in the end of the essay, several Windows Personal Fire Wall popular used in domestic and foreign currently are discussed.All the kernel technology of Personal Fire Wall which based on Windows Operation System is Windows network packet packaging and intercepting technology. And different Fire Wall holds great differences during the realizing technology of packet packaging and intercepting. In the thesis, the author depicts network packet packaging and intercepting technology under Windows Application Layer and Kernel Layer in details. The manners under Application Layer includes:LSP (Layered Service Provider), Windows 2000 packet Filter Interface, System Winsock Dynamic Link Library replacing, and so on. The manners under Kernel Layer includes:TDI Filter Drivers, NDIS (Network Drivers Interface Specification) Intermediate Driver, NDIS Filter-Hook, Win2000 Filter-Hook Driver, and so on. In addition, based on this thesis, the author considers Winsock 2 SPI programming technology which is a network packet packaging and intercepting technology under Application Layer in details.On this basis, the author raises an application about Windows network packet packaging and intercepting in Chapter Four which is the Design of Windows Personal Fire-Wall. And in Chapter Five, the author depicts the implementation of the core module of this Personal Fire-Wall. From the perspective of Software Engineering The thesis wholly introduces the whole process of development of the simple Personal Fire Wall from the fields of functional analysis, module design, file structure definition, interface design, specific coding, and so on. So, in the thesis, the readers will not only find out more comprehensive network packet packaging and intercepting technology under application layer, but also according to the method specified in the thesis, the readers can make a Personal Fire Wall based on Windows application-layer network packet packaging and intercepting technology.