By far , microsoft ’ s teredo is the only tunnel mechanism that supports nat users in a certain extent , but meanwhile has many limits such as not supporting symmetric nat , not being able to provide bidirectional ipv6 connections , having poor security , etc . silkroad exploits the client - server tunnel mode and makes use of the stateful characteristic of tunnel servers to resolve the teredo ’ s problems 目前已有的隧道机制中,只有微软公司提出的teredo协议在一定程度上支持nat 。然而, teredo实际上不能为nat用户提供双向的端到端ipv6连接,不支持对称类型的nat ,并且存在安全隐患。 silkroad采用客户端-服务器模式的系统结构,利用隧道服务器的有状态特性,解决了teredo存在的问题。
