Yes, the self hosted servers register with a centralized server to check for a license and to optionally list that server in the centralized list of public servers. Teamspeak can be hosted for free but has client restrictions that can be overcome with a license.

On a related note, Mumble self hosted servers can also register with a centralized server if the server owner wishes to have it listed for public use. This is optional as the server owner can also just advertise the connection details on a website and/or in Discord. Mumble [1] has no concept of a license to operate however. There is a light-weight version of the Mumble server called uMurmur that can run on a Linux router or RasPi but the channel configuration is statically defined ahead of time on uMurmur. The full blown version is just called Murmur and by default uses sqlite but it can also use a database like MySQL or MariaDB for storing persistent data like user registrations, channels, bans, and server configuration. .

https://www.mumble.info/

Now that money has finally run out, it looks like things are reverting back to normal.

Discord did a great job of making it easy and free to get all of your friends into a group together. Everything just works. You don’t need to have an IT person in the group to set up the server and walk everyone through connecting.

In the early days of gaming it seemed like every gaming group had at least one person who worked in tech and didn’t mind setting up a server. Now gaming is mainstream and the average gaming group doesn’t have a person who can host a server for them. Even when they do, that person would rather spend their gaming time on playing the games instead of playing the IT person for the group.

Also technically US is fault of UK too