Everyone meets on a chatroom called an IRC channel to play Outpost 2 with each other. You require a program to connect to it. To learn more about IRC setup, click here.
To play Outpost 2 multiplayer online with other people, there are two "standard" methods we use, and one "experimental" method:
Online on the internet directly - In this method, Outpost 2 uses port 47800 to join games and ports 47776 - 47807 to host games. This means that if you not directly connected to the internet, then you will have to forward data on these ports from your internet gateway to the computer you are playing Outpost 2 on. Most people have routers which connect to the internet, most of them which are able to forward the data. For more information on setting up your computer for direct games, click here.
Over a virtual network - In this method, you connect to a virtual network by downloading and using Hamachi. Regardless of occasional lag and other problems associated with Hamachi, this is the simplest method to use as it requires minimum setup and it also mean that the people who are unable configure their routers or are part of private networks are still able to play Outpost 2 online. For more information on setting up your computer for Hamachi games, click here.
Experimental: Net Fix - An experimented network fix has been created which solves many of the problems associated with the above methods. This method is not necessarily the most reliable, but is given here for the sake of completeness. A guide has been written for it. For that guide, click here.