The Research And Realization Of Application-layer VPN

Application-layer VPN as a new type of VPN solution, has become the best solution for remote secure access, and gives a new approach for implementation of LAN-to-LAN VPN. This paper takes application-layer VPN as research object. Firstly, this paper introduces SSL protocol, analyzes SSL's security characteristic, and imports PKI which closely interconnects with SSL. Then the paper introduces the conception of application-layer VPN, classifies it according to its applying mode, discusses its elements and pivotal technology, and compares it with IPSec VPN. Finally, this paper introduces the design of a LAN-to-LAN application-layer VPN solution, which is used in electronic government and based in OpenSSL, analyzes the design and implementation of the VPN's kernal module --- VPN service module and vitual device interface module, and discusses the design methodology related to the VPN's server mode. The testing and the running of this system prove the correctness, feasibility and reliability of the model put forward in this paper.