So, everything works flawlessly on LAN. My issue occurs when I use my mobile client (zoiper) on an android phone on a 4g network (WAN)
I have changed the port from 5060 to one of my liking, we will use 6050 for this example. I have also narrowed down the RTP port to 17000-18000
WAN client connects, registers, and is able to receive inbound calls, whether routed from a trunk or another extension. It transmits audio fine as the other party can hear me without issue. However I cannot hear them. I check statistics and it shows 0b received. Now I suspect this is a fire walling issue either on the 4G end (Verizon) or by my firewall in front of my PBX.
Any ideas/suggestions?