How to: DNS root server
A root server accepts a recursive resolver's query which includes a domain name, and the root nameserver responds by directing the recursive resolver to a TLD nameserver, based on the extension of that domain (`.com`, `.net`, `.org`, etc.). The root nameservers are overseen by a nonprofit called the [Internet Corporation for Assigned Names and Numbers (ICANN)](https://www.icann.org).

There are 13 DNS root nameservers known to every recursive resolver. Note that while there are 13 root nameservers, that doesn't mean that there are only 13 machines in the root nameserver system. There are 13 types of root nameservers, but there are multiple copies of each one all over the world, which use [Anycast routing](https://en.wikipedia.org/wiki/Anycast) to provide speedy responses.