What is DNS? A plain-English explanation

Every device on the internet is really identified by a number — an IP address — but nobody wants to remember a string of digits to visit their bank's website. DNS (the Domain Name System) is the directory that maps human-friendly names like example.com to the actual IP addresses computers use to find each other.

When you type a domain into your browser, your device asks a DNS resolver 'what's the address for this name?'. That resolver checks its cache, and if it doesn't already know the answer, it asks a chain of other servers — starting from the root of the DNS system down to the server authoritative for that exact domain — until it gets a definitive answer, which it then hands back to your browser and caches for next time.

DNS isn't just about turning names into addresses (an 'A' or 'AAAA' record). It's also how email gets routed to the right mail server (MX records), how domain ownership gets verified for services like Google Workspace (TXT records), and how a domain points to another name instead of an IP directly (CNAME records). You can inspect any of these with Tool King's DNS Lookup tool.

One practical consequence worth knowing: DNS records have a TTL (time-to-live) that controls how long resolvers are allowed to cache an answer before checking again. That's why a change you make — like pointing a domain at a new server — doesn't take effect everywhere instantly; it has to wait for cached copies around the world to expire, which is exactly what a DNS propagation check verifies.