[PhxHorn]

I think I got it figured out.. The router tech support finally had me open the ports using both TCP and UDP protocols, and the port now shows open. On my modem's advanced setup page, I had to click on "user" under 'applications' and then create a rule using the desired port, and then enter that port number in all three fields. I had to do this using both TCP and UDP; previously I'd only done it with TCP.