[asterisk-users] Asterisk behind NAT Early Media Video

Joshua Colp jcolp at digium.com
Tue Apr 17 08:17:49 CDT 2018

On Fri, Apr 13, 2018, at 11:56 AM, Benjamin Marty wrote:
> The current behaviour is that Earlymedia video isn't working when NAT's in
> between are involved. The source/destination IP's are correct. So the
> client is sending Early media video + Early media audio to the Asterisk
> Server "in the cloud" and the Asterisk Server "in the cloud" is sending
> both to the IP where the Client is located. But strangely just the Early
> media audio is passing the NAT to the recipent.
> My guess is that the NAT traversal for Early media audio is fine, but the
> one for Early media video not yet. Can you propably comprehend something in
> that direction? Or can you guide me to the code part where Asterisk is
> doing the Port change when a NAT is detected and the Client itself is
> sending "fake" RTP Early media traffic to get a NAT Binding for incoming
> RTP Early media traffic?

The code is in res_rtp_asterisk[1]. It's not complex and despite the comment is not specific to video. Without logs showing where things are coming from and going I don't really have anything else to add.

[1] https://github.com/asterisk/asterisk/blob/master/res/res_rtp_asterisk.c#L6140

Joshua Colp
Digium, Inc. | Senior Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - US
Check us out at: www.digium.com & www.asterisk.org

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