OS X Server Profile Manager port forwarding?

I am setting up a MDM server on OS X Server. This is just a personal project, so I am hosting off of my iMac running Yosemite and OS X Server. I have configured port forwarding and DNS records so that my domain can access the iMac. The problem is that ports 80 and 443 are unavailable (due to my ISP), and I need to forward them. I can either do domain.com:1234, or somehow tell the domain to point to port "1234" (for example?)

If I do the first option, I'll need to tell OS X Server that somehow...but I can't find the option. Is there a way to accomplish that, or to "point" the domain to a specific port by default? Thanks!