I was looking into Tailscale which I thought to be complexly open source, but it turns out that their coordination server is closed source. If you want to run your own open source coordination server, Headscale is the go-to option.
This is no fault of their own (as they freely express this in their FAQ) it’s just that I had always been told by people that Tailscale was fully open source. This got me wondering what else is not as open source as people widely accept it to be?
This is a non-sense argument. The client does all the heavy lifting while the “coordination server” is basically a glorified REST server you can in most parts replace with a web server hosting a bunch of static JSON files.
Tailscale is open source in all aspects that really matter, that being the protocols used and all aspects regarding security.