Problemes amb l'àudio utilitzant telèfon 4g

I have a FreePBX ‘VoIP Server’ installed, which I only use for the SIP PBX. It’s working on the LAN, and I don’t have any problems. The issue arises when I want to make a call with a phone outside of the LAN using 4G.

I’ve opened port 5060 UDP and done a DNAT, the device registers correctly and calls go through, but I have a problem with the audio that doesn’t work.

I’ve seen that I should open the RTP ports from 10000 - 20000 UDP for the audio to work, but when I open the port and do the DNAT, should I send it to the PBX or the phone?

I’m not sure if I’ve explained it correctly.

To the PBX. The router should be doing SNAT towards the phone, typically done by SNATing all locally originated outgoing UDP to all destinations.

Hello, Thanks for the response.
I have opened the ports on the router, and when I test the sound by calling *43, it works. However, the problem is when I talk on one phone; the other phone cannot hear me, but the reverse works. I don’t know if it’s a phone configuration issue or the router’s ports.

This can happen if you haven’t set the right external media address.

How is it configured?

It’s possible that it isn’t controllable separately from the external signalling address, via the GUI: