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.
Single Primary DNS server – Is it enough?