So it doesn't need any port forwarding, and works on CGNAT? How the "NAT hole punching" works? Both clients connect to something on IPFS?
Afaik, for DHT with torrent, clients need to know at least one tracker, what is the "tracker" here? Something on IPFS? Who am I sending my IP addresses?
How much overhead does this add to speed? I love with Wireguard, that it's barely noticeable, really close to p2p speeds, OpenVPN was awful in this regard.
First off great find. I didn't think to check the AUR. I personally wouldn't use it as that version is 3 years out of date but its existence means that it might be entirely possible to get a non Nix version. I'm not sure I fully understand why it needs Nix OS but what do I know.
It is all libp2p magic
There have been lots if talks on libp2p and Nat traversal. I suggest you check them out. How it actually works is pretty complex and requires someone more knowledgeable than me to explain. One way it works is that both devices start a TCP connection at the same time which gets the proper ports to open up.
AUR packages ending with"-git" or "-svn" always pull the latest commit from source. The version number means that was the last time the packager had to change something on the PKGBUILD script, not the actual version which would be installed.
Where should I look? Where were these talks? I'm interested.
It says it connects to a "Hole Punch Coordination (DCUtR - Direct Connection Upgrade through Relay)". So for NAT traversal to work, you need a third party, this relay. As I expected. I guess you can self host this, but than you could just host a wireguard server. I guess if you are on a locked down network where you cannot connect to any relay (e.g. how the Chinese Great Firewall works technically they could block it) you can't initiate a connection behind a NAT.
Nonetheless it seems interesting, but no magic here. Maybe the big difference that the relay servers are distributed, so no central authority to block easily.
Nix just calls the *.nix files, it's still go under the hood. PKGBUILD is similar to the flake.nix and package.nix files to me, but I have no experience with nix.
DHT is autonomous and does not require a tracker. Usually it is only used as a fallback as a regular tracker is quicker. It's p2p, and is split accross people hosting it.
Nothing too major about how it's usually used, but the yaml spec does allow arbitrary code execution when parsing a file and relies on the parser to have that feature disabled: https://en.m.wikipedia.org/wiki/YAML#Security
That's why for python, yaml.save_load() is a thing. That's fine for your local config files and may even be a feature for you, but it shouldn't be used to exchange information between services.
Tailscale... is not that good. The underlying wireguard is robust, but tailscale control plane is completely proprietary, as well as their DERP servers that it too often uses completely needlessly. They can also block you off from downloading it, updating, or logging in, if you happen to be in a wrong country.
I'm myself looking for an alternative to it, but having trouble finding something I could share with non tech savvy friends while not being as complex on my end as, say, open/strongswan ais. Any suggestions welcome.
Have you considered having Headscale on a cheap VPS? We are actually doing that and it is pretty capable. IIRC, you can configure not to use the tailscale servers at all, and use your own public VPS for coordination. Bonus point, tailscale hired the Headscale developer and maintainer, and they are allowed to work on Headscale while on their payroll. The team looks very much into FOSS.