Hi, I have problems with a SIP trunk. The final result is that I have one way audio. The sip provider is not a supported provider, so I'm not sure if all parameters are ok. but I am waiting for a reply from the provider. anyway.. i have get the ip range 10.160.250.56/30 from the provider. the problem #1 is that 3cx thinks it's an local ip.. the 3cx is on a local ip 192.168.1.249. I have looked in the 3CXPhoneSystem.ini file to remove the addresses, but I haven't found any network configuration in it.. should I just add the row with local network addresses?? my other question is about the registration settings of voip provider: so, i go to voip providers -pick the provider - advanced - registration settings -> require registration for: "do not require" (because it's a sip trunk) Which IP to use in 'Contact' field for registration: Specified IP (where I put the ip which i got from the provider), right? so, considering the ip.. what function does it really have? should it be send in the SDP packet? because, my 3cx is sending his local ip (192.168.1.249) how can I make things right?