1. ID 15 means players cannot join, or you aren't hosting. 2. If they're using the right client and port, you may not be port forwarding. You can find this option in your router. 3. You can, but *please* use it as a last resort, and use it *spefically* if you do not have access to your router settings.
Yeah, because radmin tunnels ports with people in the network. It works by faking LAN, a system where people on the same network can join you without UPNP/Port Forwarding. Double check if you have access to your router settings.
