Remote connections
It is possible to play the game over a network connection with another computer. To do so both players on both computers have to select one color played by the local player and the other by the remote player. Who chooses which side does not matter. It even does not matter if both choose to play the same player as this will automatically be interchanged by the game.
One of the computers will act as game server. Only this one can start a new network game. Also all its game data will be transfered to the client computer. You can force your computer to be server if you do not supply a hostname in the network dialog. This dialog pops up if you start a new network game. As a client you enter the hostname of the machine on which the server is running. The port does not usually need to be changed, but you can enter any valid port number there.