CGN fixed/hashed nat question

Simon Perreault simon.perreault at
Wed Jan 23 15:54:45 UTC 2013

Le 2013-01-23 16:37, William Herrin a écrit :
>> NAT traversal using port prediction is a Worst Current Practice.
> In fact, were someone to use those "worst current practices" to build
> some generic p2p VPN software, even old games could leverage it to
> allow someone behind a CGN to host.

Have a look at this:

These are the IETF's requirements for CGNs. The intent is to provide 
guidelines to vendors so that their CGNs can be as harmless as possible.

A CGN that obeys these requirements will allow NAT traversal by virtue 
of having an Endpoint-Independent Mapping behaviour. That is the BCP. 
Not port prediction.


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