What is Master (Primary) DNS zone?

What is a DNS zone?

The domain namespace in the Domain Name System (DNS) is divided into various segments, with different managers in charge. The administrative responsibility can be delegated to a person, company, or organization. This separation is good for redundancy and better distributes the administrative load.

The Internet’s domain namespace has a hierarchical design. Un is the root domain (the dot after .com), then is the domain name like domainname.com, and under it, there are subdomains like mail.domainname.com or ftp.domainname.com.

Each of these areas can be managed separately with its own Master DNS zone.

A DNS zone has inside DNS records and settings of a DNS namespace. This last one can have one or many DNS zones managed for a specific host or service. All this zone information is saved in a DNS zone file that has the DNS records.

Those records have a mapping between DNS names and their IP address, services and servers, verification purposes, and more. 

The process works this way. A web browser has to obtain the IP address of a specific hostname. It starts a DNS search, meaning it is looking for the DNS zone file that has information for the domain. Then it is directed to the DNS server in charge of the management of the DNS zone for the specific hostname. The server we talk about is known as an authoritative name server for the domain. This server finally resolves the DNS search, meaning it provides the necessary IP address and the rest of the data for the requested hostname.

It’s worth mentioning that authoritative DNS servers do their job due to the data that are saved directly in their system. This kind of server doesn’t work caching query results.

Commonly, authoritative DNS servers can be found where the DNS provider is or where the site is hosted.

You can create DNS zones from your DNS provider’s control panel and manage them. 

What is Master (Primary) DNS zone?

There are different DNS zones. Let’s explore the Master zone, also called the Primary zone.

Actually is better to refer to them in plural. Master zones are the ones that have the zone data (read-write). The management of the domain is divided into different Master zones, and only one could exist for a particular part. 

Suggested article: Why use a Managed DNS provider? 

All these data records are saved in .txt, a standard text file, mainly because it is not hard to be backed up or recovered if needed to check or solve an issue. This is a big advantage .txt offers.

To add info or make changes to the DNS zone is totally possible. The only factor to consider is that the authoritative server must be up, working properly. If this server is down, the Master or Primary zone won’t be available.

To get the benefits and redundancy of a Managed DNS, the zone data must be accessible on different servers (multiple). So you will need copies of these Master zones. With a reliable Managed DNS provider the copies are automatically distributed over all name servers.


Having a clearer knowledge about DNS infrastructure design and the elements it is built with will be useful for you to manage it easier.

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