2014-03-27 44 views

回答

0

正如selbie所說,UNSAF在RFC 3424中定義,意思是UNilateral Self-Fixing。

當客戶端在NAT後面時,它不知道他的外部地址。根據這個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.