I've encountered this problem Many times before and found it Very frustating. Enough to make me quit whatever I am doing, but I am tired of this. I've searched high and low in the internet, from professional to developer communities and still havent found one, so I hope someone here helps me.
I've been trying to port forward my Motorola vt2442-vd since I can remember. I've called Costumer support, and found myself yelling at them because no one had any idea what they were telling me.
I've set up DMZ and still no port is forwarded. I've disabled windows firewall (managing services/on start up), I have no AV installed in my computer anymore (removed a couple of days ago to see if this was the problem).
Setup is cable -> modem -> router -> PC
modem does NOT have firewall settings, and firewall is turned off in router.
I have DHCP settings (but IP's never change, it is set to only 2 devices which is wireless and my computer).
Also I should add that when testing in http://canyouseeme.org I do not get connection refused, but connection timed out