What is a domain name?

A name instead of a number

Every website lives on a computer with a numeric address, called an IP address. Numbers are hard to remember, so the internet uses domain names instead: words like fmtechub.com. When you type one, your device looks up the matching number using a system called DNS, which works like a phone book. See What's an IP address? for the number side.

How a domain name is built

Read a domain from right to left:

• The ending, called the top-level domain, such as .com, .org, .uk or .lk. Some are for countries, others are general.
• The main name, just to the left of the ending, such as fmtechub. Together with the ending, this is the part someone actually owns: fmtechub.com.
• Subdomains, further to the left, such as www. or mail.. The owner of the main name can create as many of these as they like.

So in help.example.com, the owner is whoever holds example.com. In example.com.login-check.net, the real owner is whoever holds login-check.net. That second pattern is a favourite trick of criminals.

Who owns domain names?

Nobody buys a domain forever. You rent it, usually by the year, from a company called a registrar. As long as you keep paying, it stays yours. If you forget to renew, someone else can register it once it expires. Organisations that manage each ending keep the official records so that no two people own the same name.

Reading links to stay safe

Criminals register names that look close to real ones. Watch for:

• Extra words: yourbank-secure-login.com is not your bank.
• Swapped letters: arnazon.com (r and n instead of m) or a zero instead of the letter o.
• A different ending: yourbank.co instead of yourbank.com.
• The real name hidden on the left: paypal.com.account-help.info belongs to account-help.info.

Tip: Find the last dot before the first single slash. The word just before that dot, plus the ending, is the real owner. Our URL tool can split a link into its parts for you.

Try this

1. Open a website you use often and look at the address bar.
2. Identify the ending, the main name and any subdomain.
3. Next time a message contains a link, do the same before you tap. If in doubt, type the site name yourself instead.

Want the technical version? Read DNS explained.

Why businesses care about their domain

A domain is part of a business's identity. Customers learn it, emails come from it and search engines link to it. That is why organisations often register common misspellings and other endings of their own name, so criminals cannot use them. If you run a small business or a club website, set your domain to renew automatically and keep the registrar account protected with 2-step verification. Losing a domain can mean losing your website and your email at the same time.

Email addresses use domains too. A message from support@yourbank.com uses the bank's domain, while yourbank.support@gmail.com is just a free account anyone could create. The same right-to-left reading habit works for email addresses: look at what comes after the @ sign.