During the last month, I talked with my ISP (Cox) and arranged for the commercial cable to be installed at my home along with a static ip. Our understanding was that I would be running web servers, etc. and that ALL ports would be available and not restricted in any way.

I have a second system which is connected to the standard home cable/internet with a dynamic ip. It is on a seperate cable modem and router (same brand/models). It has none of these problems. So I doubt that the ISP is involved or restricting.