Do you know the difference between a Master (Primary) and a Slave (Secondary) DNS zone?
What is a DNS zone
First, let us explain what a DNS zone is. DNS zone is a container of DNS settings and DNS records of a DNS namespace. The DNS namespace can have single or multiple DNS zones, each managed by a particular DNS host/service. This division helps for the administrative purposes. It is like an enormous pie, each piece of it allows better separation of the administrative load and helps with redundancy.
Don’t directly associate a DNS zone with a specific domain. A DNS zone may contain multiple domain names or a single one; the important thing is that it is used for controlling a fraction of the namespace. DNS zones can be on the same servers too.
Different types of DNS zones
There are different types of DNS zones, but in this article, we will set our eyes on just two:
• Master (Primary) DNS zone
• Slave (Secondary) DNS zone
Master DNS zone
Master zones, contain a read/write copy of the zone data. There could be only one Master zone on one DNS server at a time. All the DNS records added manually or automatically, are written in this Master zone of the DNS server.
The data is stored in a standard text file – .txt. The advantage is that it is easy to back it up and to recover in case of problems.
Something essential is that to be able to make changes to the DNS zone, the master zone must be available. If the server with your Primary DNS is down, you won’t be able to make any changes.
If you want to have redundancy, you must have the zone data accessible on multiple servers.
If you want to learn how to create a Master zone in ClouDNS, check the following step-by-step tutorial:
You can also check our wiki page about Master DNS zone.
Slave DNS zone
The Slave zone is a read-only copy of the zone data. Most of the times Slave DNS zones are copies of Master zones. They can also be copies of other Slave zones or Active Directory Zones.
If you try to change a DNS record on a Secondary zone, it can redirect you to another zone with read/write access. By itself, it can’t change it.
One of the primary purposes of a Slave zone is to serve as a backup. When the master zone is down, it can still answer requests for the zone from its copy.
Watch the following video tutorial on how to create a Slave (Backup) DNS zone:
If you want to use Slave DNS zones, you can also review our Secondary DNS page, and decide which of our premium plans is right for you.
Now you know what a DNS zone is and the difference between these two types – Master DNS zone and Slave DNS zone. For any additional questions about your DNS infrastructure, you can contact our customer support.