No voice/audio on inbound/outbound calls

Sangoma Trunking
1

After a recent firewall upgrade, I cannot get audio for any outbound or inbound phone calls. Trunking is working, I believe it’s something with the SIP handshake that’s getting lost. Looking at the debug logs, nothing jumps out at me as an issue. I’ve read through the other posts to no avail. I’m pretty sure this is a network issue, just not sure where to start.

Here are the odd balls…

  • If an inbound call is invited and acknowledged, I can hear the internal phone from the external phone but the external phone does not transmit internally
    *Rebooting the PBX does nothing
    *The new firewall has packet inspection active whereas the old “firewall” was a Netgear Nighthawk. Tried turning it off and there are no changes.
    *Firewall ports are open for 5160 to the PBX from the trunk IPs
    *SIPSTATION is the trunking provider

I’m scratching my head trying to hunt down where this dies.

2

Confirm you have the full RTP range 10000-20000 forwarded thru the firewall to the PBX. Ensure that the external IP address is set in Asterisk SIP Settings correctly, the all local subnets are defined, and that NAT is set to static. If the router has a SIP ALG (they might call it packet inspection) then disable it.

3

It would appear that the NAT static setting was the culprit. It was set to public IP originally but all seems to be resolved now.

Thanks for the quick fix!

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4

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