Address (A) records direct a hostname to a numerical IP address.  For example, if you want mycomputer.yourdomain.com to point to your home computer (which is, for example,, you would enter a record that looks like:


Important:  You must put a period after the hostname.  Do not put periods after IP addresses.                  




CNAME allows a machine to be known by one or more hostnames.  There must always be an A record first, and this is known as the canonical or official name.  For example:


yourdomain.com.  A


Using CNAME, you can point other hostnames to the canonical (A record) address.  For example:


ftp.yourdoman.com.  CNAME  yourdomain.com.

mail.yourdomain.com.  CNAME  yourdomain.com.

ssh.yourdomin.com.  CNAME  yourdomain.com.


CNAME records make it possible to access your domain through ftp.yourdomain.com,  mail.yourdomain.com, etc.  Without a proper CNAME record, you will not be able to connect to your server using such addresses.


Entering a CNAME record


If we wanted home.site-helper.com to point to site-helper.com, we could enter the record in two ways:



The first method allows you to simply enter the subdomain.  Do not put a period after the subdomain name.



The second method requires you to enter the entire hostname, followed by a period.

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