I can get my Iphone 3Gs [ios5, no jailbreak, no cydia] to register via wifi while inside the local LAN. However I cannot get the phone to register outside the LAN using 3G. I do have the router set to allow port 5090 through to the 3CX server. I have tried a variety of settings on the Iphone to try to get it working but no joy. Does anyone have any suggestions?