So as we know, to turn a home PC into a server that’s accessible for public requires setting from router to point the public IP to the computer in LAN that you want to use as server. But apparently Tor servers doesn’t requires settings from routers. You can just run
sudo tor and your server can be access through unique .onion domains.
So I’m wondering what technology does Tor uses to make server be available to access through public by .onion domain while you don’t need to configure routers, as that’s the key to make your computer to be accessible from public?