Connecting over the internet

Hi there,
I’ve probably readed all posts related to this topic, but still can’t answear my question.
I know that you can use Steam to connect 2 players over the internet without port forwarding and IP’s and stuff lke that.
But my question is whether or not you can use Steam’s Nat punch without actually publishing your game on Steam?
I want to make a very simple multiplayer game using Listen Server, but I don’t want to force anyone to port forward and enter commands and whatever… you get the idea.
If it’s not possible to use Steam that way, is there another way to “Nat Punch” somehow and connect 2 players over the internet?
I saw EOS’s Nat thingy, but I have no idea how it works and if it can do the job.
Thanks in advance!

P.S I have also noticed that at the beginning of some MP games, when you start the game for the first time, it asks you to allow something related to Windows Firewall. Just wanted to ask if this is somehow related to the process?

Yes, you can use their test appid to test and run your game on their subsystem, but you’ll be unable to sell it, only give it away until you have an app id.
You interface with and host games how you normally would, but after following the setup process:…m-ccc89bd8d8a9

I meant if I can use it for the final product, I know about the dev id, but at the end you are forced to publish on steam or use a different method :confused: