What is a CNAME Record?

What is a Canonical Name or CNAME?

A canonical name (CNAME) is a type of database record in the Domain Name System (DNS) that shows that one domain name is a nickname or alias for another domain name. The CNAME, which is also called the "true name," is especially important when more than one service runs from the same IP address.

People often use the CNAME instead of an A record, which is a type of DNS record that shows a domain's IP address. The target of CNAME records must be a domain, not an IP address. A domain with a CNAME record can point to either another domain with a CNAME record or a domain with an A record.

How do Canonical Names work?

When the "www" subdomain is set to be an alias for the root domain name, a subdomain like www.samplesite.webname.com will have a CNAME record that points to the root domain webname.com.

So, when a DNS server looks up the DNS records for blog.samplesite.com, it will also look up webname.com, which will restart the query using the canonical name. Then, it gives back webname.com's IP address through its A record. So, in this case, the real name of samplesite.webname.com is webname.com.

If the IP address of the host changes, the only thing that needs to be changed is the DNS A record for the root webname.com. Any changes to the root will automatically affect all CNAME records, including blog.webname.com.

Uses of Canonical Name Records

Here are a few common ways to use CNAME records:

• to send visitors from several websites owned by the same person or group to the main website;
• to give each network service, such as File Transfer Protocol (FTP) or email, its own hostname and point it to the root domain;
• to give each customer a subdomain on the domain of a single service provider and use CNAME to point the subdomain to the customer's root domain; and
• to register the same domain in more than one country and point the versions for each country to the main domain.

Where can I find my CNAME?

You may find your CName record by manually checking it, via your DNS dashboard when you update it, or via online look-up tools such as at www.whatsmydns.net

Updating a CNAME Record

To learn more about updating a CName Record, please see How to Update CNAME Aliases - Canonical Name - DNS Management

Related Articles

DNS Records Explained - Domain Name System Management
How to Update DNS Records - DNS Management