EarthNet Ports

From InsideEARTH

Earth 2150 requires the following game ports to be open and forwarded, if they are not then you will not be able to connect to or host multiplayer games.

To Join Games: TCP/UDP 2300-2400
To Host Games: TCP/UDP 47624

You can use the following guides if you're unsure how to forward ports on your router to your PC: PortForward