What is DNS?

It takes a fraction of a second and about four steps.

1. Your computer asks a resolver — usually your internet provider’s — where yourbusiness.com lives 2. The resolver asks the root and the registry which nameservers are responsible for it 3. It asks those nameservers for the record it needs 4. The nameserver answers with an IP address, and your browser connects to it

The result is cached at every step, which is why the second visit is faster — and why a change you make is not visible everywhere at once.

• A — points a name at an IPv4 address. This is the one that puts a website somewhere
• AAAA — the same thing for IPv6
• CNAME — points a name at another name, so www can follow the main domain
• MX — says which server handles email for the domain. Get this wrong and mail stops
• TXT — free text, used for SPF, DKIM and DMARC (email authentication) and for verifying ownership with services like Search Console
• NS — says which nameservers are authoritative for the domain

Every one of those is editable from your client area, at no charge, whether or not you host with us.

Every DNS record carries a TTL — time to live — which tells resolvers how long they may cache the answer. A TTL of 14400 means four hours, so a resolver that asked ten minutes ago will keep giving the old answer for nearly four more.

That is the whole of "DNS propagation". Nothing is travelling anywhere; caches are simply expiring at different times.

The trick: lower the TTL to 300 seconds a day *before* you plan a change. Then the switch takes five minutes instead of a day. Put it back afterwards.

Changing nameservers

Hands the whole domain to a different DNS provider. This is what you do when you move hosting and want the new host to manage everything.

Changing a record

Keeps the same DNS provider and changes one answer. This is what you do to move a website while leaving email where it is.

People often change nameservers when they meant to change one record, and wonder why their email stopped. If mail matters, change the A record and leave the MX alone.