Domain Name Registration > Domain Name Servers

What is a zone record?

Zone records contain DNS information about a domain or sub-domain and are contained within your zone file. The most common records contained in a zone file are start of authority (SOA), name server, mail exchanger, host and CNAME. These are described below.

Start of Authority (SOA)

The SOA record is required for every zone file. This record contains caching information, the zone administrator’s email address and the master name server for the zone. The SOA also contains a number that is incremented every time the zone file is updated. When this number is changed, it triggers the DNS to reload the zone data.

Name Server

This record contains the name server information for the zone.

Mail Exchanger (MX)

The MX record provides the mail server information for that zone. This allows email to be delivered to the correct location.

Host (A)

The A record is used to map an IP address to a host name. This is the most common type of record on the Internet.

Canonical Name (CNAME)

A CNAME is simply an alias for a host. CNAMEs allow you to have more than one DNS name for a host. CNAME records point back to the A record. So if you change your IP address in your A record, all your CNAME records will automatically follow the new IP of the A record. The alternative solution is to have multiple A records, but then you would have multiple places to change the IP address which increases the chances of error. Using CNAMEs is just more efficient.

Also see What is a zone file