What is a CNAME Record?

Understanding the CNAME (Canonical Name) Record

A CNAME Record (or "Canonical Name Record") is used to map an alias name to its real, canonical domain name. Instead of pointing directly to an IP address, a CNAME record points to another domain name.

For example, if you want www.example.com to show the same content as your main site at example.com, you can create a CNAME record pointing `www` to `example.com`. When a client requests `www.example.com`, the resolver receives the target canonical domain `example.com` and automatically performs a subsequent lookup to retrieve the target's IP address.

Structure of a CNAME Record

Here is an example showing how subdomains are configured to route through external hosting servers:

Query a CNAME Record in Real Time

Enter a subdomain below to query and resolve its active CNAME targets:

The CNAME Root Restriction (Apex Rule)

According to the core DNS specifications (specifically RFC 1034), a CNAME record cannot exist on the **apex domain** (also called the root domain, like example.com).

This is because a CNAME record overrides all other records for that exact host label. If a CNAME were placed on the apex domain, it would block the MX (email routing) and NS (nameserver delegation) records from executing, causing severe DNS failure.

To circumvent this limitation, many modern DNS providers offer synthetic record types, such as ALIAS or ANAME records. These emulate CNAME functionality at the root level by resolving the target IP addresses on their server side and returning them as standard A/AAAA records.