基于IPSec 的VPN 模型采用傳輸加密報文的形式，實現了企業重要數據的安全共享。網絡復雜性的增加以及一些高端的網絡應用需求已迫使對VPN 的模型做優化改造，引入策略管理和策略授權協議，設計基于策略服務協議的隧道模式的 VPN 安全網關模型，成功的實現了高端網絡對訪問控制與審計、動態IP技術以及WLAN 的需求，提高了網絡安全管理的效率。
關鍵詞：策略協議；CA；VPN 網關；隧道
Abstract: In the form of encrypted messages, the VPN model based on IPSec realizes secure share of the primary data among enterprises. The increased complication of the network has entailed optimization and transformation of the traditional model of VPN. By introducing policy management and policy authorization protocols, and devising the secure gateway model based on the tunnel model which adopts policy service protocols, it has successfully fulfilled the demands of the advance network for access control, auditing, dynamic IP
techniques and WLAN, and accordingly enhanced the efficiency of the network security management.