​Primary DNS server – What does it mean?

When you talk about networks and domain performance, it’s impossible not to mention servers. The complex structure networks, especially the large ones, couldn’t work without the participation of many DNS servers. 

But there are different types of servers. The functions they accomplish are defined by their position in the domain name system (DNS). If you wonder what a Primary DNS server means, here you have what you need to know.

What is Master DNS zone and how does it work?

Primary DNS server – What does it mean?

All existing DNS zones in the DNS namespace need a server to save their complete DNS data. Such a server is called a Primary DNS server or Master DNS server. It’s very important because it contains the original data of a specific DNS zone, meaning all the files – DNS records needed for its functionality.

The Primary DNS server is critical for network administrators and your business because it’s the only one that allows you to modify, add, or delete data. Being the original source, it will save all the changes you need to make. After, it will propagate these updates to the rest of the servers in your network (Secondary DNS servers) via a specific process known as DNS zone transfer. Therefore, what other servers (Secondary ones) will have is just a readable copy of the data that will be updated every time a change is made or every time you program it to happen. 

A Primary zone can only be hosted on one Primary DNS server. You can have a Secondary Zone, a copy of it, on various Secondary DNS servers. You can not make modifications to any DNS record of the domain on a DNS copy. Secondary DNS servers are a common and recommended practice to get redundancy and increase uptime. 

Due to different reasons, it can happen that a Primary DNS server is not available, and it can not respond to requests. In such a case, the requests can be responded to by the Secondary DNS servers because those servers have a copy of all the DNS records in their cache. 

A Primary DNS server contains the updated DNS records. They are saved in a DNS zone file. There you can find records such as:

  • A or AAAA record. They show the IP address of the domain. The difference between them is that the A record shows an IPv4 address, while the AAAA record shows an IPv6 address.
  • CNAME record. It points one domain to another one (true name).
  • MX record. It points to the mail server in charge of accepting emails on behalf of a domain.
  • TXT records. They are used mostly for verification processes (SPF, DKIM, DMARC, etc.).

These are part of the basic records, but there are more, and all are directly linked with specific domain functions. So, as you see, Primary DNS servers contain essential information.

How to keep a Primary DNS server secure?

Hide the server! It’s a fact you should only allow the necessary people to access it, basically your administrators. The more you limit the access to the Primary DNS server, the fewer risks of hacking or malicious alterations for your network and business.

Hiding the server doesn’t affect the responding process for requests. Your domain will be available, and requests will be answered properly by the Secondary DNS servers configured for being authoritative for the zone. 


A Primary DNS server holds really sensitive data, and it’s one of the keystones for your domain to be as competitive as you expect. So secure it, and avoid unnecessary risks!