Controllers?

[Alayan]

But when you say 'setting up a WAN server' (or LAN) - correct me if I'm wrong but doesn't a server relate to a physical machine running and connected to the network somewhere? I.e a third machine?

Server in English can both mean a program that provides data/service to other programs (on the same computer or through a network), and a computer dedicated to running server programs. To refer to the computer, it's better to use other terms if the context may leave doubts.

There is nothing preventing a normal computer from running a STK server. It's not a very good idea for WAN because it exposes your IP and there are often routing issues preventing users from connecting to it, but for LAN that's not an issue.