VPN is one of key technologies on the Internet that allows users to access securely to resources in a domain via unsecure networks. For hierarchically nested security domains, such as an R&D division domain in a corporate domain, In such organizations, some existing VPN schemes with multiple security gateway traversal function is applicable for a user to access to the innermost security domain from the Internet. However, most of existing schemes have some drawbacks in terms of security, efficiency and availability. In this paper, we propose a new way to remedy these shortcomings using proxy gateways. The proposed method connects two deeply embedded security domains by a series of virtual paths to create a single VPN link; and by incorporating a proxy gateway to accommodate communication between clients and the security gateway, this permits secure and highly efficient communications without modifying the client or server.