CNAME RecordDomains & DNS

CNAME records define an alias for canonical name for your server (one defined by an A or AAAA record).

For instance, we could have an A name record defining the "server1" host and then use the "www" as an alias for this host:

server1     IN  A
www         IN  CNAME   server1

Be aware that these aliases come with some performance losses because they require an additional query to the server. Most of the time, the same result could be achieved by using additional A or AAAA records.

One case when a CNAME is recommended is to provide an alias for a resource outside of the current zone.

Related Terms1