What is CNAME?

Question: What is CNAME?

Answer: A CNAME or Canonical Name record is a type of record found in DNS that allows the user to specify an alias for a domain name. For example, you can create an alias of domain1.com with domain2.com. More typically, however, it is used to create aliases for subdomains, including the most common, which is “www”.

Often a default domain record will have a wildcard (*) that will resolve any subdomain, including “www”. If it does not, it will need something like this:

www.domain1.com. CNAME domain1.com.

You can also have one point to another:

ftp.domain1.com. CNAME sftp.domain1.com.

Many mail servers will also use a mail subdomain:

mail.domain1.com. CNAME domain1.com.

CNAME records are also very useful when pointing to external domains, particularly when using cloud services like Google Apps. It effectively disguises the fact that the service is hosted on another domain.

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