It may be your ISP.
It is difficult to figure that you can access port 80 through your router, but not connect directly. It may be your ISP does not allow any routing for more than one ip address per customer. That is a possibility. I have a static public ip connection like that. If I get a dhcp issued ip, I can't connect to that ip from the internet.
That is a possibility. I will investigate further with my ISP. The project will be implemented with a static public IP, which may work around the issue.
Until I figure out what is up with the DHCP Public IP I will continue to use a router in-line and progress the code.
Thank you