DNS Unpacked

Every time you open a website, a quiet chain of lookups turns a name like example.com into the address of a server. This guide takes that chain apart one piece at a time, in plain language, with each claim linked to the standard or documentation it comes from.

Read it front to back, or jump to the chapter you need.

What a domain name actually is
Names for people, numbers for machines: what a domain name is and the problem it solves.
Reading a domain from right to left
Top-level domains, second-level domains and subdomains, and how the hierarchy fits together.
Who runs domains: registries, registrars and ICANN
Who is responsible for which part of the domain system, and what you are actually paying for when you register a name.
What happens when you type an address
A step-by-step walk through a DNS lookup, from browser to root server and back.
Resolvers and caching
Why most lookups never reach the authoritative server, and what that means for speed and changes.
Nameservers: where a domain's answers live
What nameservers are, how delegation works, and what changes when you move them.
A and AAAA records
The records that connect a name to an IPv4 or IPv6 address.
CNAME records
Aliases: when to point one name at another, and the rules that limit them.
MX records
How mail servers are found for a domain, and what priority numbers mean.
TXT records
Free-form text records, and why so many services ask you to add one.
TTL and why DNS changes take time
Time-to-live values, caching, and what "propagation" really means.
Pointing your domain at a website host
The practical steps for connecting a domain to a website, and how to check it worked.