networking - rfc 4787 中 UDP 的 UNSAF 方法

Question

我正在阅读 rfc 4787，作者提到了 UNSAF 方法。什么是 UNSAF 方法？

Answer 1

正如 selbie 所说，UNSAF 在RFC 3424中定义，表示单边自地址修复。

当客户端在 NAT 后面时，它不知道他的外部地址。根据这个 RFC：

As a result of the nature of Network Address Translation (NAT) 
Middleboxes, communicating endpoints that are separated by one or
more NATs do not know how to refer to themselves using addresses that
are valid in the addressing realms of their (current and future)
peers.  Various proposals have been made for "UNilateral Self-Address
Fixing (UNSAF)" processes.  These are processes whereby some
originating endpoint attempts to determine or fix the address (and
port) by which it is known to another endpoint - e.g. to be able to
use address data in the protocol exchange, or to advertise a public
address from which it will receive connections.