# What is DNS (domain name system)?

> DNS is the internet's address book: settings attached to your domain that tell the world where your website and email are actually hosted.

- Source: https://nerdsharks.com/glossary/dns
- Publisher: Nerdsharks (Exeter, Devon, UK)
- Updated: 2026-09-26

Also called: domain name system, DNS records, nameservers, A record, MX record.

Computers find each other using numbers, called IP addresses. DNS translates your easy-to-remember domain name into the right numbers, so typing your address loads your website and emails to you reach your inbox.

It works through a handful of records set at your registrar or DNS provider. An A record or CNAME points your website to your host. MX records point email to your email provider. TXT records prove ownership and help stop other people sending email pretending to be you.

Changes can take a while to spread around the world, sometimes minutes, occasionally longer, which is why a website move can briefly look different to different people.

## Why it matters for a small business

DNS is the bit that silently breaks things. A wrong change can take your website or email offline, and a missing email record can send your quotes to customers' spam folders. Whoever manages it should know exactly what each record is for.

**Example:** An electrician moves her website to a new host. The A record is updated to point at the new server, and the MX records are left alone so her email keeps working throughout.