Hello, I have a 3CX Phone System V12 6.2. Here's the scenario, I'm going to use false IP addresses but I'm sure you'll understand: NIC1 - 18.104.22.168 NIC2 - 22.214.171.124 Public IP - 126.96.36.199 We use the NIC1 IP to communicate with internal phones and the public IP to register outside extensions (3CX Phone). However, we added a NIC2 interface so that we can communicate with our service provider. We followed the instructions, NO default gateway, and a static route to the provider's IP. So far so good, we have connectivity with no issues. At first, everything was wrong, I had to change the SIP parameters to the ones that the provider was hoping to receive (basically the host parts of the parameters), the 3CX always puts the external IP!!! The thing is, that when we place an external call passing through the new SIP trunk, I see From: ok, To: ok, P-Asserted Identiy: ok, Contact: ok, but on the SDP messages, I see: c=IN IP4 188.8.131.52 the PUBLIC IP...but why?? How can I change that? I have one way audio because of that (can't hear from the outside), I get "No RTP received from X.X.X.X to Extn IP=184.108.40.206...the provider is always expecting to receive the 220.127.116.11 IP from the NIC2, not the public IP address. Can you help me solving that please? EDI: I forgot to say that I already changed in VoIP Provider Advanced Tab to use the 18.104.22.168 IP, but no luck. Thanks in advance.