I spent over an hour on the phone with Comcast technical support for business. Thankfully they know a heck of a lot more than the residential folks. At one point he got frustrated with me and all my questions. Then he logged into my computer and keyed some username and password that gave me full access to my modem for our session. I was able to verify all the settings and literally I opened the box up to world. There is no firewall running, there is no ports being blocked etc.
I ran this test http://qos.bluip.io and passed with flying colors. No ALG on SIP!! I would post a link but my IP’s are listed there. Then I used a terminal session to start checking ports to a VPS machine. Other than 25 all necessary ports are open and responding.
The box is sitting on the outside world and has a static IP. I am using Google DNS too!!