Multiple Areas on One Server

I wonder how to do a Server that has Multiple Areas where the Players could be.
I want to have a Downloadable Server (Like Minecraft has) which supports multiple Areas like Minecraft’s Normal, Nether and End worlds. Or for example an Animal Crossing type of Game where you enter a house and there’s an area just for that.
I’m working with UNet and don’t understand how to have multiple Collision Worlds etc. on one single Server

One option is to have them in the same scene, but beyond the furthest potential view distance (perhaps as layers, one at a height of 0, one at a height of 3000 etc). If it was a Minecraft style thing, you could filter world update messages based on which area the player was in, as well as their distance from such events.

There’s something about loading scene additively, though I think that might load one scenes objects into another, rather than running two simultaneous scenes on one server.

Alternatively you might be able to run multiple headless servers on one box, each serving a particular environment. Then your players can hop from one server to the other.

The running multiple headless servers, sounds good, but doesn’t it have to rely on multiple ports? and how’s performance if the user has the server and game on the same machine? not on servers on the internet

Yes you would need to have a range or set of ports forwarded to that machine and have each server on a different port (I think UNet will fail to initialize a second server on the same port on one machine). It might need a beefy machine to handle it, that would be down to testing I suppose.

That’s not what I want them, it should be one Port and a not so good machine that can still handle it, a server like minecraft has. Is it possible to write the Server in C# and build own collision worlds in it and connect Unity Clients to it?

you can create a custom visibility networkbehaviour that implements the Observer methods. This allows clients to only see a subset of GameObjects
http://docs.unity3d.com/Manual/UNetVisibility.html