What is a domain name?

Every device on the internet is reached by a numeric IP address, such as 93.184.215.14. People don't remember numbers, so we use domain names like insidx.com instead.

The parts of a domain

Read a domain from right to left:

• .com is the top-level domain (TLD). Others include .net, .org and country codes such as .eg and .sa.
• insidx is the second-level domain: the part you register.
• www or mail in front are subdomains, which you create yourself at no extra cost.

Who is involved

• The registry runs a TLD. Verisign, for example, runs .com.
• A registrar sells domains to the public and talks to the registry for you.
• ICANN coordinates the whole system and accredits registrars.

When you "buy" a domain you are really renting it for one or more years. If it isn't renewed, it expires and eventually becomes available to anyone.

Ownership details

Each domain has a registrant (the owner) and contact details stored by the registrar. WHOIS privacy hides those details from public lookups, which cuts down on spam.