Integrated Application Of L2tp And Ipsec Method Of Study

With the developing of information technology and the expanding of internet application, security of Internet becomes more and more importmant. For enterprises, physical private network is secure, but it is expensive. The technology of Virtual Private Network (VPN) is the major way to solve the contradiction of security and expenditure.L2TP and IPSec are most extensive VPN. L2TP can support remote-visiting and many transmiting-protocols, but its security is not enough. IPSec can support security on IP layer, but is short of many transmiting-protocols. Therefore, combining IPSec and L2TP, learn from others's strong points to offset one's weakness, can construct a better VPN which can support many transmiting-protocols, as well as authentication and encryption.In this paper, we analyze the open sound code realization software L2TPD and ISAKMPD of L2TP and IPSec, summarize their realization principle, configure two softwares and runn them in Unix OS separately. By modifying the realization code of L2TPD and ISAKMPD, this paper realizes the combination of L2TP and IPSec, accordingly, providing a VPN which can satisfy users' demands better. On the basis of the combination of IPSec and L2TP, this paper puts forward a multi-security-connection technology, tests and confirms by experiments. VPN based on multi-security-connection can offer loading proportion and fault-tolerance, and it has high dependability and flexibility. This paper realizes VPN technology based on VLAN (Virtual Local Area Network). Finally, this paper tests the VPN system which combines L2TP and IPSec, analyzes the experiment results, and summarizes the whole research work.