What is DNS?
The domain name system, the internet's phone book.
Computers find each other with numbers called IP addresses. But you type names, like google.com. Something has to translate. That's DNS.
What it is
DNS, the domain name system, is the internet's phone book. It turns a domain name into the IP address of the server behind it.
How it works
When you type a name, your device asks a DNS resolver. If it doesn't already know, the resolver asks the root servers, then the servers for .com, then the servers for that domain, which hold the real answer. The answer gets cached, so the next lookup is almost instant.
Why it matters
It means a site can move to new servers without changing its name. And when a site is down for everyone at once, DNS is a classic suspect.
