Implementation of virtual private networks at the transport layer

Abstract

Virtual Private Network (VPN) solutions mainly focus on security aspects. Their main aims are to isolate a distributed network from outsiders and to protect the confidentiality and integrity of sensitive information traversing a non-trusted network such as the Internet. But when security is considered the unique problem, some collateral ones arise. VPN users suffer from restrictions in their access to the network. They are not free to use traditional Internet services such as electronic mail exchange with non-VPN users, and to access Web and FTP servers external to the organization. In this paper we present a new solution, located at the TCP/IP transport layer that, while maintaining strong security features, allows the open use of traditional network services. The solution does not require the addition of new hardware because it is an exclusively software solution. As a consequence, the application is totally portable. Moreover, the implementation is located at the transport layer; thus, there is no need to modify any software previously installed, like FTP, Telnet, HTTP, electronic mail or other network applications.