No audio when forwarding external to external

I

iexos

New Member
Jan 30, 2026
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We have set up FusionPBX with Sipgate and almost everything works fine.

We have set an extension to forward all calls to an external number. When calling this extension from an external number the call is forwarded correctly and the connection is established but there is no audio in any direction. The call is terminated after 10 seconds.
On the other hand when actively forwarding after accepting the call from external with a local phone and then forward to an external number it works as expected. So involving the phone seems to do smth different.

FusionPBX is behind a NAT and registered to the Sipgate gateway. The local phones are all in the same network as the pbx.
Does this use case require some NAT settings that the other do not?
Are there any other settings that need to be changed in Fusion?

We have only found a similar issue description and solution for cisco here: https://community.cisco.com/t5/coll...on-hair-pinned-calls-on-the-cube/ta-p/3676035
They mention Media Flow Around or Media Anti-Trombone to solve this but we couldn't find anything similar for Fusion/Freeswitch

Thank you for any ideas on this!
 
Thank you for this idea. I don't really know where exactly this should be set so I have tried:

- adding to the outbound rules1775144747857.png
I can also see in the logs that this is set before executing the bridge

- setting it in external and/or internal profile
1775144907432.png
(Ein = enabled)

Still no sound unfortunately. Any other ideas where this should be set?
 
Sorry I can't be of more help, I have never had to do this because we don't have any switches behind NAT. You could try export bypass_media=true.
It will probably help you to get some packet captures and look at what IP addresses and ports are being specified in the SIP SDP bodies.
 
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