You don’t need any game network to do it, you can start the server and connect via ip address, same as multiplayer been mostly done 10 years ago and still soem games does that like Minecraft or still popular old Valve games does to this day., it most simple and default to do multiplayer, because thats how internet works.
But before you start up the server you need to forward the port on router, so router forwards data coming in to port from public IP to port of selected private IP. by default UE4 use port 7777 and this is one you should forward. So you need access router configuration, it similar on each but access it is diffrent for each:
This need to be done only on server side, other clients can connect to forwarded port from private IP without a issue… i mean you connecting to websites and other servers without doing that right? ;]
Now you can starting up the server:
“Listen Server” is a server with client turned on, simply one player hosts the game, “Dedicated server” runs server without client turned on, it standalone server where people can connect, graphics rendering is compliantly turned off and server only do physics and game logic and sends state to clients
Now client connect to your public IP and forwarded port, either by starting up with ip in command line explained in link above, or by game code using ClientTravel function:
.or “open” commend in console which can be also done in blueprint
And that it.
Once Epic Online Service will develop more it should be a lot easier as regurgitating products there is free and without any evaluations and you can run tests more easily
I really recomad you to setup a server on computer connected to network via Ethernet cable, as WiFi is not really reliable to run servers, if you use WiFi yo can expect some lag. There also possibility that ISP gives you private IP as internet one, dynamic changing IP can be a issue too, IP changed midway will break connection with all clients, with IPv4 address pool is fully drained this becomes more and more prominent issue, some ISP also don’t want there users to host servers too.