Yealink T23G openvpn pfsense freepbx one way audio

[Chen Kang]

I'm going to first describe my setup. I have internal IP phones where phones and freepbx are on the same LAN. This setup works fine.

I also have remote users who wants to use the T23G. We have existing working OpenVPN/pfSense setup. So I add the VOIP network into OpenVPN and exported with OpenVPN client export. There is a specific export for T28 and I used that and imported the tar file into the T23.

On to the T23G phone. I brought the T23G home. Turn it on and on first glance, everything looks good. VPN icon is on and the number is registered. I tried calling the office numbers. It rings and someone in the office picked up. I can hear the other party but the other party cannot hear me. Then after 30 seconds the call is dropped.

I am puzzled. OpenVPN connection is established as verified on the phone and pfSense webui. Number is registered and verified in the phone webui. There is a log entry in freepbx.

[2017-08-03 09:55:20] NOTICE[1715] chan_sip.c: Disconnecting call 'SIP/814-00000053' for lack of RTP activity in 31 seconds

This let me to consider if the T23G somehow cannot send UDP packets to freepbx. However this is conflicting as the SIP connection is also on UDP and seems to work fine.

Any tips for a quick fix from experienced users?

Firmware Version 44.81.0.110
Hardware Version 44.0.0.16.0.0.0
FreePBX 12.0.76.2
pfSense 2.3.3