I am using a DDWRT router. I have a SIP phone system in the DMZ of the router. I can call out, but cannot receive calls. The packet capture on the SIP server, shows "error 404 - forbidden" when the number is called. To test, I went to a website that checks for open ports, and told it to check for the port I am using, on my WAN address. Port is reported closed. Being the port i am querying, is actually on a device behind the WAN address, and that port is not really being forwarded to the device, however the device is in the DMZ, is that the expected behavior? How to test, if that port can be reached from the outside.