What a CNAME record is
A CNAME record, short for Canonical Name record, points one name to another name rather than to an IP address. When a resolver finds a CNAME, it restarts the lookup using the target name and follows that name's records, such as its A or AAAA records, to reach the final address.
How it works
Suppose www.example.com has a CNAME pointing to example.com:
- A lookup for
www.example.comreturns the CNAME targetexample.com. - The resolver then reads the A record for
example.com. - The visitor connects to the address that A record provides.
This keeps configuration tidy, because you only maintain the address in one place and let aliases follow it.
Why it matters
CNAMEs are widely used to point subdomains at third-party services like content delivery networks or hosting platforms, where the provider may change the underlying IP at any time. Because the alias resolves to the provider's name, your record keeps working without edits. One important rule is that a CNAME cannot coexist with other record types on the same name, which is why the root domain usually uses an A record instead. You can inspect a domain's aliases with the WhatIP dns-lookup tool.