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What are the characteristics of an Authoritative DNS Server?

What is an Authoritative DNS server?

The Authoritative DNS server is an essential part of every DNS network. It stores all of the important DNS data, including the DNS records for a specific domain. That server could belong to a domain registrar or a DNS hosting provider. 

A lot of authoritative servers cover various areas. They also provide responses to the queries, but just for the DNS zones they are set up for.

Every Authoritative DNS server has two main purposes. The first one is to store and keep the database of one or several domain names and their analogous IP addresses. The second duty of this server is to supply the recursive DNS servers with answers such as the accurate IP address for each domain requested by a user. 

It is crucial to remember that the authoritative server does not cache the results of queries. The reason for that is because it operates with the original data that is stored straight in its system.

Types

  1. Primary DNS server (Master DNS server) – It holds the original zone file with all DNS records. The administrator of the DNS zone only makes adjustments to the DNS records here in the Master DNS server. Every Slave DNS server receives the updated data via a mechanism called a zone transfer.
  2. Secondary DNS server (Slave DNS server) – Every Slave DNS server is an actual copy of the Master DNS server. That means different servers are capable of providing an answer to the DNS queries. It is necessary to note that you can’t make any adjustment to the DNS records inside a Secondary DNS server. Yet, you are going to have added points of presence (PoPs) that could reply to queries of the DNS resolvers.

Authoritative DNS server vs. Recursive DNS server

The Authoritative DNS server contains the original source of the DNS data, including the DNS records. On the other hand, the Recursive DNS server could only provide a copy of the DNS data if it’s still accessible in its DNS cache. That depends on the time-to-live (TTL) value established for the various DNS records.   

In case the TTL has been expired, and the data is not available there, the Recursive DNS server is going to produce a whole new search through the Root server, TLD server, when eventually it reaches the Authoritative DNS server. There it is going to receive an answer with the required DNS records finally.

How to check the Authoritative DNS servers?

You can easily check your Authoritative DNS server by using the NSlookup command. It is a simple tool available on Linux, macOS, and Windows. The DNS lookup for the NS DNS records is going to show you all the nameservers for the domain.

First, you have to open the Terminal on Linux and macOS or the Command Prompt on Windows. Next, just write the following:  

nslookup -type=ns exampledomain.com

You are going to receive a list of all of the nameservers for that particular domain, plus their analogous IP addresses. Just make sure to replace “exampledomain.com” with the domain name you wish to check. In addition, you are able to check every nameserver separately. That way, you examine if they respond accurately.