中文摘要：

IPv6隧道代理面向分散用户，是IPv4／IPv6过渡技术的重要组成部分。但IPv6隧道代理不支持NAT用户，而在世界各地尤其是在中国，NAT用户广泛存在。该文针对NAT问题对隧道代理机制进行了修改，允许隧道主体上存在任何类型和任意数量的NAT。在Linux平台上实现了修改后的隧道代理系统，并对隧道服务器的性能进行了测试。

英文摘要：

The IPv6 tunnel broker is designed for scatted users and is an important mechanism of transition from IPv4 to IPv6. However, the mechanism does not support NAT users, which generally exist in the world widely. especially in China. The mechanism is modified to allow NAT users to connect with IPv6 networks. The system is implemented on Linux platforms and the performance of the tunnel server is tested.