RTP to non-standard port when call goes to voicemail

I have encountered an issue where on a SIP trunk between two Asterisk servers, only calls that are not answered, go to a non-standard RTP port and the Voicemail service is not handled by Asterisk

Example 1 - Everything Works
A Calls B, B answers. Good to go

Example 2 - No RTP in Voicemail
A calls B, B lets the call go to Voicemail. Voicemail Application activates, but no RTP is received.

After receiving RTP pakcets from the far side server the near side responds on a non-standard port. Shown in the trace below.

I have checked the rtp.conf and the start and end range match on both sides.


Anything else I should look for. I am looking at any firewall port forwarding or blocking, but I do not think thats the case here.


prtpstart? Is that a typo or did you copy it exactly as it is?

Where is the trace for the failure case?

ah. yeah that is a typo in the post, that is not present in the config file. cant seem to find an option to edit the original post though.

I cant provide the whole trace, but if there’s a portion of it that would be helpful I can see about getting that.

Portions generally don’t help. You have to understand the full situation and everything involved. For example you mention a firewall, if NAT is involved then it could be using a UDP port mapping outside of the configured page.

And the portion that was obviously missing was the one that exhibited the symptoms.

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.