A record

What it does

Every server on the internet is reached by a number. People prefer names. An A record joins the two: it says that example.com lives at a particular address. The A stands for address. Its sibling, the AAAA record, does the same job for the longer IPv6 addresses.

A name can have more than one A record. Browsers then pick one of the addresses, which some hosts use to share the load or to keep a site up if one server rests.

A record or CNAME

This is the question most people arrive with. The short answer: an A record points at a number, a CNAME points at another name.

• Use an A record when your host gives you an IP address, or when you are setting up the bare domain (the apex).
• Use a CNAME when your host gives you a host name, usually for a subdomain such as www.

A CNAME is easier to keep correct, because the host can move servers without you editing anything. An A record needs updating if the host's address changes, so copy it exactly and keep a note of what was there before.

A common setup

Many sites use both. The apex example.com gets A records with the host's addresses, and www.example.com gets a CNAME to the host's name. Then you pick one as the main address and send the other to it. Our www or non-www entry explains that choice.

Checking your records

Before you change an A record, write down the old value so you can undo it. After the change, the old answer can linger for a while because of the record's TTL. The DNS checker shows what your name points at now. For Mini Casa, the custom domain guide lists the records to add. Custom domains are in preview, so the records appear in your dashboard when domain connection is available for your account. See the custom domains page for what is ready today.