your domain has dns records

example.com A 1.2.3.4 300
example.com is the name
A is the type of record
1.2.3.4 is the value
300 is the TTL

these records are cached on lots of servers

server 8.8.8.8, thinking: I was told example.com’s IP is 1.2.3.4

but when that cache expires…

the only source of truth is your authoritative nameserver

your nameserver: I have all example.com’s DNS records!

how to get a domain’s authoritative nameserver: ask its TLD namesever

person: who’s the authority for example.com?
.com nameserver: b.iana-servers.net

here’s how to look up example.com’s nameserver

Run this:

$ dig ns example.com
g.gtld-servers.net

g.gtld-servers.net is one of the .com nameservers

you can update your nameserver on your registrar’s website

person: hey I want to use a different nameserver
registrar: I’ll tell the TLD nameservers!