A CNAME (canonical name) record is a DNS record that can be used to create an alias for the domain and allow traffic for the domain name to be redirected somewhere else. CNAME records allow a machine to be known by more than one hostname. There must always be an A record for the machine before aliases can be added. The hostname of a machine that is stated in an A record is called the canonical, or official name of the machine. Other records should point to the canonical name.
Example CNAME Record:
mail.first.mydomain.com. IN CNAME first.mydomain.com
