Based Ipsec Vpn Gateway

In recent years VPN has developed quickly and turned into a new network technique. By encryption and authentication, VPN is to build private, fast and safety network through Internet. Its advantage is not only to save large cost and expense but also to make sure the date safely transport. The project chooses to realize the VPN based on the host, because it can resolve some problems such as safety problem, access control and verification problem cased by remote access users, and the internal server of the company need not to be exposed in Internet and can continue to adopt the private address. The project inserts the protocols under the windows operate system to realize the VPN gateway design. This realization makes users need not to have too many computer knowledge and can easily use the software, which can satisfy the need of the common users. Overall the cost is low. This project is still adapted in the remote access fields such as remove on-line copy the form, maintenance and diagnose. In this thesis firstly analyze and study the VPN technique, especially the current popular protocols that are L2TP and IPSec. Then study and analyze two kinds of VPN models, find out something use for reference, and put forward the project that is to insert protocols under the windows operate system and use the VC++ to realize the VPN gateway based on IPSec. In the chapter 5th, combined with the item, elaborate the design thought, structure and the work principles, particularly the IPSec mold charged by me, and give the data structure and methods used to realize the IPSec mold. At last, the thesis sums up the fields the project is adapted to and puts forward the main direction of the further study work and some problems needed to be resolved further.