Hi we are evaluating the 3CX system and are overall very impressed. We have a VOIP provider (EntaNet) who are supplying an external landline number. When I use X-Lite externally to our firewall it rings fine. I've configured 3CX on a private IP address behind our Fortigate-60B firewall (in NAT mode) and outgoing calls are working fine but we can't seem to get any incoming calls to work. The Fortigate seems to have extensive SIP support and I've been through the documentation and tried various things but it constantly fails the firewall tests and I can't get any incoming calls working. I've tried the recommendations made by posters here none of which seem to work. Has anyone got this working in this configuration ? Attached a very simple network diagram.