Primary DNS server explained.
You can find the Primary DNS server, also called the Master DNS server, so you can see that the names show its importance. Yet, it is the origin of all the original information concerning a particular DNS zone and its corresponding domains. The Primary DNS server has a very responsible role. It stores all the DNS records for its DNS zone. Whenever you want to make some changes or delete one record or several, you have to do it in the main source – the Master DNS server.
The place of the Primary DNS server is on top of other servers because it is the authoritative one. For that reason, when you make changes on it, they propagate to the rest of the servers and get updated. Furthermore, because it carries the IP addresses, with much more domain’s DNS records, its purpose is essential for the DNS resolution process to be performed.
Definitely, there is not one but numerous Primary DNS servers because there are many separate DNS zones and various networks. However, when we are speaking for a particular DNS zone, it is possible to have only one Primary DNS server.
Although, the servers except the Primary are typically Secondary DNS servers. They serve as additional copies of the original zone data to keep the domain available in any situation, plus to provide redundancy. The copy in these servers is only readable, and you are not able to make any modifications to the DNS records there.
How does it work?
Each time a user makes a request for a domain name, a translation from a human-readable language into machine one (IP address) occurs. For instance, when domain.com is requested, the IP address (188.8.131.52) for that website has to be located.
The Primary DNS server stores the original zone file. That is a specific file that holds the authoritative DNS information for a domain with all the DNS records. The IP address is also saved there.
The Master DNS server is the source of the DNS data, and it has to distribute this data with the Secondary DNS servers. That way, they are also able to answer DNS queries for the domain. Otherwise, it has to respond to the queries alone.
When a domain is requested, a recursive server performs a search for the IP address. That is going to be given by a Master DNS server or a Secondary Authoritative DNS server.
In order to keep the Primary DNS server safe, it is usual practice to have Secondary Authoritative servers. They respond with authoritative answers to the queries.
How to protect a Primary DNS server?
You can consider hiding the Master DNS server and keeping your network protected. Actually, it would be best if you only let the required people have access, which means your administrators. As much as you limit the access to your Primary DNS server, the less is the chance for hacking or malicious modifications for your network and business.
In addition, hiding your server won’t change the process of responding to requests. They will be answered accurately, and your domain will be available.