DNS CNAME (Canonical Name) Record

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DNS CNAME

A DNS CNAME (Canonical Name) record is used to create an alias for a domain name, mapping it to another domain name instead of an IP address. It allows multiple domain names to point to the same destination without needing separate IP addresses.

How a CNAME Record Works:

If you create a CNAME record like this:

Hostname: www.example.com

Record Type: CNAME

Value: example.com

✅ When someone visits www.example.com, the DNS server redirects the query to example.com. The DNS resolver will then look up the A record for example.com to get the IP address.

Example Use Cases:

Pointing Subdomains:

www.example.com → example.com

Branding for Services:

mail.example.com → ghs.google.com (Google Workspace)

Content Delivery Network (CDN):

cdn.example.com → cdn.cloudflare.net

CNAME Record Rules and Restrictions:

✅ Alias to a domain name, not an IP address.

✅ Multiple CNAMEs can point to the same target domain.

❌ Cannot be used for the root domain (apex domain). Use an A or ALIAS record instead.

❌ CNAME loops are not allowed: a.example.com → b.example.com → a.example.com.

CNAME vs. A Record vs. ALIAS:

Record TypePurposePoints To

A RecordMaps a domain to an IPv4 address192.168.1.1

CNAME RecordMaps a domain to another domain nameexample.com

ALIAS RecordRoot-level domain redirection (like CNAME)example.com → IP