If you are just starting to manage your Domain Name System, you should have a clear view of the different terms, and the DNS zone is one of the essentials. So, let’s explain a little bit more about it!
DNS zone – Definition
The DNS zone represents a small segment of the Domain namespace. Despite its size, it has a crucial purpose which is to allow different DNS administrators to have control and manage different parts of the global DNS system. That is the main reason this worldwide naming database (DNS) is decentralized.
Additionally, there is a large number of DNS zones, and some of them are actually stored in the very same DNS server. Let’s say, for example, one precise DNS zone can be responsible for .info, example.info, blog.example.info, etc. If we take a look at a particular subdomain as a separate website, it should be handled with dedicated administration. That means the subdomain is going to need a different individual DNS zone.
The collection of DNS records, like A, AAAA, MX, TXT, PTR, and so on, is created and kept in the DNS zone. It is important to mention that the first DNS record, the SOA record, also contains fundamental details about the zone, DNS administrator, and some parameters (Refresh and Retry rate), which are essential for DNS zone transfer.
DNS zone types
Primary zone (Master zone) – It is the fundamental and main source of DNS data for a specific domain name. Here, the DNS administrator is able to create, add, delete or modify DNS records and manage the domain name. Note that if you want to adjust and modify some of the DNS data (DNS records), you should complete this task in your Primary zone. Then, via a DNS zone transfer, all of your Secondary DNS servers are going to obtain the new information and update their copies.
Secondary zone (Slave zone) – It is a simple duplicate of the Primary zone (Master zone). Yet, it is a read-only copy. That means the Secondary DNS contains all of the DNS data (DNS records), but the DNS administrator does not have the ability to make any changes in this DNS zone. Instead, it receives the read-only copy through the process called DNS zone transfer. Additionally, you can find it called in other ways, such as Backup zone or Slave zone.
Reverse zone – It is also an administrative element of the domain name space that holds DNS records, like the Forward (Primary) zone. Yet, it acts in exactly the opposite way. It is used to connect the IP addresses (IPv4 or IPv6) to the related domain name. Therefore, when you implement a Reverse DNS service, you should create the Reverse zone. We should mention that this zone has limitations, and it is able to hold just a small number of DNS record types. They are PTR record, SOA record, and NS record.
Parked zone – The Parked zone is perfect for parked domains. It gives you the ability to use a web page with a contact form, title, and description. It is often implemented for domain names that are for sale or websites that are under construction.
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