libzt VS GameNetworkingSockets

BlindSPOT: https://blindspotsec.com/ Specific graphic from BlindSPOT: https://blindspotsec.com/wp-content/uploads/2021/04/Failure_Before.jpg How to Measure Anything in Cybersecurity Risk: https://www.amazon.com/dp/B01J4XYM16/ Monte Carlo simulation approach: https://embracethered.com/blog/posts/2020/red-teaming-and-monte-carlo-simulations/ D3FEND: https://d3fend.mitre.org/ ATT&CK mappings: https://github.com/center-for-threat-informed-defense/attack-control-framework-mappings ATT&CK evals: https://attackevals.mitre-engenuity.org/index.html CALDERA: https://github.com/mitre/caldera Offensive Countermeasures: https://www.amazon.com/dp/1974671690/ SPIFFE: https://spiffe.io/ SPIRE: https://github.com/spiffe/spire Zerotier: https://www.zerotier.com/ Zerotier libzt: https://github.com/zerotier/libzt

Keep in mind that if you do go the GodotSteam route, there's GameNetworkingSockets from valve that doesn't have the requirement of needing Steam that you can use for releasing on other platforms. It has the same interface as the Steamworks SDK without requiring the Steamworks SDK.

Their UDP-but-connection-based game networking protocol can be used completely separetely from Steam (it also supports encryption). I think that does not include their relay networking solution, but still.. maybe it's helpful. They also have a TCP-like interface to make it easy to plug into an existing solution.

If you want to go the route of using a raw protocol and packing your messages yourself, I suggest to at least have a look at Valve's GameNetworkingSockets either for inspiration of what you might need or even to just use the library: https://github.com/ValveSoftware/GameNetworkingSockets

There is early NAT piercing support in Valve's GameNetworkingSockets. Check out:

You can also try Valve's GameNetworkingSockets with a serialization of your choice.

I do wonder if you'd get better performance if the clients connected to an adapter running on the local machine, and those adapters then communicated through the bridge over UDP. Valve made their networking library opensource, so you could just directly use that. It'll do the p2p STUN stuff for you, and if that fails you could route the traffic through your server(s) (and at least it will UDP behind the scenes, so hopefully less acknowledgement latency).

Inconsistencies can be prevented by ensuring the server handles all operations and does so in a given order, then transmits the results to clients. I wrote a little about this for my game Avoyd a long while ago. Clients (including a client running the server) send an edit request via reliable ordered UDP (e.g. using Enet, Raknet, Steam Networking etc.) and the server places these in a single queue then performs the edits and sends the results back also using reliable ordered UDP.

https://github.com/ValveSoftware/GameNetworkingSockets Works with AND without Steamworks.

If you want to try a known library, I think Valve might have a good one (didn't test this myself, though): https://github.com/ValveSoftware/GameNetworkingSockets If you search for "C++ game development P2P library" you can find some suggesting on SO (but without having tested some and having an idea on what you really want, it will be hard to pick one).