I'm trying to use an application called Jacktrip with a friend of mine. He has an N450 WiFi cable modem and I set up port forwarding for him because the app uses port 4464 UDP. I'm not sure what is causing the problem, but the software works internally in my LAN between our computers, just not over the Internet. His router's public IPv4 address is not pingable from my PC, but mine is pingable from his PC. The same goes for IPv6.
