I have the UCM6202 with SIP Trunk configured and some GXP phones in LAN.
UCM is behind the Mikrotik router. Everything is working fine (internal and external calls).
Lately I configured soft-phones outside this LAN that are connecting to UCM through Internet.
Everything is OK when I’m using soft-phone to call other extensions (GXP in LAN or even other soft-phones).
The problem is when I’m trying to call any external number (through SIP Trunk) from soft-phone. I’m getting only one -way audio.
SIP and RTP ports are forwarded from router to UCM
PBX Settings - > SIP Setting -> NAT
- external host is set (static public IP of the router)
- Use IP address in SDP enabled
- local network addresses configured
NAT option for SIP Trunk is disabled
Extensions for soft-phone has NAT enabled and Direct Media disabled.