Re: [BEHAVE] p2p applications using STUNT and EIM NATs for TCP

Dan Wing <> Thu, 20 June 2013 03:50 UTC

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From: Dan Wing <>
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Date: Wed, 19 Jun 2013 20:50:11 -0700
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Subject: Re: [BEHAVE] p2p applications using STUNT and EIM NATs for TCP
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On Jun 18, 2013, at 10:25 AM, ivan c <> wrote:

> Hello,
> Does any of you has examples of applications that use a STUNT server together with an EIM NAT for TCP?
> This is the single purpose (besides the convenience of the implementation) of having an EIM NAT in the first place: performing port prediction with the help of a STUNT server.
I don't think you mean 'port prediction' where the software is trying to guess the next-used port ("predicting"), but I believe you mean learning the external IP address and TCP port (by talking to a TCP server on the Internet) and communicating that learned address/port to a rendezvous server of some kind (DNS server, SIP server, game server, whatever).

> Surprisingly, I am not aware of any applications that rely on that. All the p2p applications that I know of use different techniques for TCP Hole Punching or use other alternatives, such as UPnP, port forwarding, etc.
I found this discussion of folks utilizing TCP hole punching (as I summarized above) for their projects,


> It would be important to somewhat quantify the usage of this technique in the wild.
> --
> Ivan Chollet
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