Question regarding connecting two computers without an internet connection

[CubesAndPi]

My friends and I play various games on dolphin during spare at school. Obviously, the network there is horribly slow, so online play is out of the question. What I am wondering is this: Is it possible to connect two computers with a CAT 5e cable and have multiplier functionality on something like Mario Kart DD LAN mode without having to connect to the internet? Thanks in advance!