That's kinda of something I'd prefer not to do, considering that that would probably knock out all the other computers behind the NAT. I might give it a try at some point when I can do so without affecting anyone else.

I did try some things - adding JJ2 to the port forwarding or open ports list didn't work, setting the built-in firewall to allow fragmented UDP packets didn't work, and setting the firewall to echo blocked packets to me didn't work either (and nothing new appeared in the packet sniffer).