FreePBX remote user on Android phone -- no audio.



  • Due to a VPN bug on Android 8.1 I cannot use a VPN for this use case so am attempting to rely on the responsive firewall in Fpbx 14 along with port forwarding via an ERL.

    I have forwarded 5060 and 10,000 to 20,000 as per the documents and the user can successfully connect with the FreePBX instance using Zoiper and AdoreSoftphone.
    The issue is that the user can place a call but receives no audio.
    The asterisk logs show the connection, the call being established, et al and no errors.

    I've been fighting with this for days and cannot figure out why one would not receive audio.
    I have attempted to configure STUN in FreePBX and matching STUN in Zoiper but the issue persists.

    Connecting to FreePBX while on the same LAN works without issue so it's definitely a NAT or routing issue.

    Does anyone have any suggestions on what to check next?

    Thanks!



  • STUN is only on the client, not needed on the server.



  • Got SIP ALG on your firewall? That’s almost certainly the issue.



  • Thanks @scottalanmiller, I disabled sip alg on the ERL as the first step in diagnosing; I had forgotten that it comes enabled on these.
    I didn't realized that STUN was only needed on one side as the FreePBX interface does provide a place to enter it. Regardless, this didn't fix my issue.

    Is there anything else I should be checking? Firewall is configured to allow, NAT is configured appropriately, ports are specified as matching FreePBX. Connection can be established and calls can be initiated, just no audio.

    I'm really pulling my hair out over this one...



  • Aside from moving this instance to a cloud provider such as vultr, is it "OK" practice to place FreePBX on a DMZ and let the responsive firewall control access? I'm always worried about placing devices outside of the firewall.



  • @manxam said in FreePBX remote user on Android phone -- no audio.:

    Aside from moving this instance to a cloud provider such as vultr, is it "OK" practice to place FreePBX on a DMZ and let the responsive firewall control access? I'm always worried about placing devices outside of the firewall.

    Yes, that's the expected use case.



  • On a related note, dealt with a client today that had pfSense running in front of their PBX. that was annnoying. There is no "SIP ALG" button, but you have to setup a static outbound NAT rule to fix it.


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