Authoritative and Recursive DNS: What’s the Difference?

For many people, DNS is a mystery. In fact, it’s not uncommon for the average person to not know what it is at all. If you’ve ever tried to explain DNS to someone who is the plug-n-play type, you know what I mean. They start off listening enthusiastically but after about 30 seconds, sometimes less, their eyes start to glaze over and you’re woefully aware of the moment their mind runs off to “anywhere else but here.”

Even for those of us who do know about it, DNS can get complicated the further you go down the rabbit hole. The difference is we know how important it is—and cool. Yeah, DNS is cool. Don’t think so? Stick around and see why.

The Basics: What is DNS? 

Invented by Paul Mockapetris in 1983, the Domain Name System (DNS) is a hierarchical system that operates much like a translator. It converts domain names to unique numeric internet protocol (IP) addresses for every single device that connects to the internet. This includes computers, smartphones, Alexa, Google Home, modern cars, smart lights, smart refrigerators—you name it.

It’s not that the internet can’t run without DNS, it can. You could manually type the IP address of every website you wish to visit, but this isn’t practical—especially in today’s online-centric climate. The thing is, there are billions of websites. Just remembering the numeric IP addresses for your top 10 favorite sites would be challenging for most people. 

Think about it. When was the last time you remembered a phone number that wasn’t stored in your phone or that you didn’t search for online? But there’s another issue with manually typing in IP addresses into a web browser. IPs change, and some, quite frequently. 

A popular way to explain the Domain Name System is by comparing it to a phonebook, and for good reason. A “phonebook” for web addresses is very much like what DNS is. But this phonebook is dynamic. Even if there was a printed version of every domain name and its corresponding IP address, it would become useless pretty fast due to the rapid pace at which things change online. Not to mention the fact that new websites pop up every day.

What is Recursive DNS?

We’ve talked about the basics of what DNS is, but there are also different kinds of DNS and it’s important to make the distinction between them. First, let’s talk recursive.

Re·cur·sive - adjective
: of, relating to, or constituting a procedure that can repeat itself indefinitely

Any device or system that accesses the internet uses recursive DNS. As soon as you type a website into your browser, perform a search, or access an online-based application, your request is sent to a recursive resolver.

What is Authoritative DNS?

Au·thor·i·ta·tive - adjective

: possessing recognized or evident authority: clearly accurate or knowledgeable

Authoritative nameservers are like directories for web addresses. They store the most up-to-date information about domains and their associated IPs and provide recursive resolvers with the final answer for user queries. 

The DNS Process

Upon receiving a request, a recursive resolver either answers a query with information it has in its cache or contacts a root server. The root server then refers the recursive nameserver to an appropriate top-level domain (TLD) server (com, net, org). The TLD then sends the recursive server to an authoritative nameserver, who then provides the final answer to the original request.

The buck stops here for 99% of the lookups on the internet, but the process will repeat if necessary until a final answer is received.

Who Uses Recursive DNS?

Any device or system that accesses the internet uses recursive DNS. As soon as you type a website into your browser, perform a search, or access an online-based application, your request is first sent to a recursive resolver.

Most people rely solely on recursive DNS—typically that which is provided by their Internet Service Provider (ISP). Due to the plug-and-play nature of an ISP’s DNS, many people don’t bother searching for alternatives or even know that there are other DNS options available to the public. 

Who Uses Authoritative DNS?

Authoritative DNS is used by small and enterprise-level businesses, as well as individuals that own a domain used for professional purposes. Anyone who owns a domain name needs authoritative DNS—otherwise, no one will be able to find it on the internet. 

Using enterprise authoritative DNS is critical for businesses as it is more secure, higher-performing, and has more features. There are both free and paid authoritative DNS providers, but organizations are better suited with premium options. 

The Key Differences Between Authoritative and Recursive DNS

Authoritative and Recursive DNS go hand-in-hand. Both depend on the other to do their “job.” There are key differences between them, though. 

For one, recursive servers only store a temporary copy of the “domain phonebook” and often have to get an answer for a query from another server. In this way, they’re like the guy who knows a guy that knows a guy. The authoritative servers, on the other hand, always hold the most accurate version of this digital phonebook and are able to provide a final answer for user queries.

As mentioned earlier, recursive DNS is used by everyone and is necessary for any device that connects to another resource on the internet. Most recursive DNS provided through ISP services lacks advanced features such as the use of EDNS client subnet and the customization options many authoritative services provide. 

While the free recursive DNS supplied by most ISPs offers satisfactory performance for the majority of home users, it is not a good choice for businesses or individuals that own their own domain.

Authoritative DNS is like the person that everyone comes to for help. These servers are the ones that provide the final answers for DNS queries/lookups. Enterprise authoritative DNS, specifically, provides users with faster speeds, better performance, increased security, and higher uptime, which makes it a necessity for organizations and individuals running online businesses. 

Without DNS, the Internet World Would End as You Know It

Without the Domain Name System (DNS), the internet as we know it today wouldn’t exist. You know the gazillion Google searches you do? All those websites you visit or all that online shopping? The way you socialize and find news on the web? All that great music you find … all the Gifs and memes you share? None of that is happening without DNS. See? DNS is cool, now isn’t it?

If you liked this, you might find these helpful:

https://constellix.com/support/what-is-dns

‍https://www.experfy.com/blog/software/what-is-a-dns-server-and-why-the-internet-wouldnt-work-without-the-dns-system/

https://umbrella.cisco.com/blog/what-is-the-difference-between-authoritative-and-recursive-dns-nameservers

‍If you’d like to learn more about Constellix’s advanced DNS features, book a personalized demo or contact one of our sales specialists.