Authoritative DNS server explained

There are different types of servers – TLD, root, recursive, authoritative DNS server etc. If you think that all of them are the same and comply with the same objectives, that’s a mistake. They are teammates, but definitely, there are differences between them. Today let’s talk about Authoritative DNS servers. What exactly are they for? Why do you need them? Here it will be explained! 

What is an Authoritative DNS server?

An authoritative DNS server is the holder of the zone file that contains the DNS records. And in this case, we don’t talk about a copy of them but the true DNS records. For this reason, it’s the exact and only place the master zone can be managed from and where edition or any kind of modification to DNS records can be made.

This is the server that can accurately respond to the DNS queries taken by recursive servers. For example, when a user requests a specific domain from a browser, a recursive server will look for the corresponding IP address of that domain. First, it will check if the IP address exists in its cache. In the negative case, it will search through different servers until it reaches the authoritative DNS server that can provide the information.

To summarize, this type of server complies with two very important missions. It stores the list of domain names and their associated IP addresses. And it responds to the recursive servers’ queries while providing accurate DNS information. Without those answers, the DNS resolution process couldn’t be completed, and users could not reach domains.

Since the role of authoritative DNS servers is essential, there are many of them executing these tasks all across the world.

What are the types of authoritative DNS servers?

Yes, as we mentioned before, there are different types of servers. And even within the same category, like the authoritative DNS server, there are differences. In this case, there are two types, primary and secondary authoritative DNS servers. 

The primary or also called the master authoritative DNS server is the one that has the original zone file and the DNS records. Every time a domain administrator has to add, delete or modify DNS records, this will be made exactly in this server type.

This primary server must inform and share updates that include the modifications on DNS records that occurred within its zone file. It has alternatives, for instance, the NOTIFY function. Through it, the primary notifies the secondary server about an update so it can request it. Another alternative is pushing a zone transfer to all secondary servers.

And the secondary, also called a slave authoritative DNS server, is a copy of the primary or master server. The secondary works as a backup but also, it’s useful for spreading the traffic load. Yes, having more nameservers able to respond to DNS queries, the traffic can be handled faster and more efficiently. Those servers will mean more PoPs (points of presence) for you to respond to recursive servers queries.

Something very important to underline about Secondary authoritative DNS servers is that modifications to DNS records can not be executed from them. They hold copies! 

Conclusion

As you already know, the domain name system (DNS) involves different components to execute vital processes for the Internet and domains to exist and operate successfully. There’s no doubt how important an authoritative DNS server is in this context. Simply, without the information they contain and the updates they allow and share, to find something on the Internet would be like trying to find a needle in a haystack!

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