Port forwarding failure on 2WIRE 2701HG-B

I've enabled DMZ mode on my router, and disabled every manner of firewall. Given, I only use Comodo and my Windows Firewall hasn't been enabled in any fashion for a long, long time. Using the port checker tool at www.yougetsignal.com always returns that nearly all of my ports are closed despite adding application profiles to the firewall exceptions in the router GUI, and enabling DMZ mode once that apparently didn't work. I've attempted pinging the ports on my routers public IP, and the ports still read as closed. Is it just not possible on this router, despite it appearing to support it so simply?

 

All of the info you need to know can be found at http://www.portforward.com.

 

Also, depending on what ports your trying to port forward, isps block certain ports.