"It does some doohickey with the internets."
'What is DNS?' is a question that comes up often in our line of work. You would think a company whose target audience is DNS professionals that this question would not come up, but it does. A lot, actually. And there's a reason why.
In the 'Friends' episode The One with Ross' Thing, there's a scene where, in pursuit of trying to identify some skin growth, Ross ends up at a "guru," and the following dialogue ensues:
Guru Saj: As I suspected, it's a kundus!
Ross: What's a kundus?
Guru Saj: I don't know, what's a kundus with you?
I've been writing about DNS for years now, and I feel like the question really isn't 'What is DNS?' but instead 'What is DNS with you?'
Ask a dozen people what DNS is, and you'll get 19 different answers. (Because of course Karl will try to be funny and give you seven instead of one. Damnit, Karl!) Those answers will range from quoting Wikipedia ("The Domain Name System (DNS) is a hierarchical and decentralized naming system for computers, services, or other resources connected to the Internet or a private network.") to "I don't know, it does some doohickey with the internets" accompanied by a slight shrug.
The funny thing is, none of those answers are wrong. DNS, or to use the name on its passport Domain Name System, is a network service with the primary task to connect domain names to IP addresses. It's basically why you can type keanuisimmortal.com into your browser and not remember 18.104.22.168. Or 22.214.171.124. Because, you see, it's not as simple as it looks.
Despite what you might think, a single domain name can point to multiple IP addresses. And when we say 'domain name,' there's a difference between www.keanuisimmortal.com and keanuisimmortal.com. Technically. Practically, often (and in this particular case) none. (We broke down the parts of a domain name in this blog post.)
In addition, DNS isn't just a "phone book" for the internet. That analogy is inaccurate, and also, who uses phone books anymore? (Also, DNS has no ads for car repairs and home massages. It could, though, at least technically; and we're ever thankful that it's not a common practice.) DNS stores, or can store, a lot of information: a variety of verification keys and certifications (the digital equivalent of a biometric ID), simple text to verify ownership for a domain (which assumes that you're the owner based on the fact you have access), encryption keys, to name just a few.
Wikipedia lists 47 active DNS record types, 4 pseudo record types, and 43 obsolete record types. Clearly, there's a lot more going on here than just helping you out by translating keanuisimmortal.com into something your computer and router and the doohickeys that make up the internet can understand.
As much as it pains us to say this, Karl is right. (But still: damnit, Karl.)
Your definition of DNS entirely depends on what you do with it.
If you're an end-user, DNS may be simply the magic that makes your interneting a lot more bearable. (Also, kudos to you, reading a DNS blog.)
If you're a system administrator at a tech lab, DNS might be your daily battleground, as your users are filing tickets for new or changed subdomains faster than you thought it was humanly possible. (Also, welcome to our DNS (and DHCP and IPAM) blog! We have more content for you; feel free to explore.)
If you're a business executive, DNS may be a line in your company's cost analysis. (And if you're wondering why it's so damn expensive, or how can you lower it, come this way.)
We have virtually infinite space in this blog, and yet we'd find ourselves filling it up to list all use cases of DNS. 'What is DNS?', therefore, entirely depends on who you are and what you do with it.
Since you asked:
DNS is the DNA of networks. Quite appropriately. Have you ever seen a DNA helix? Same kind of thing. If DNA is the blueprint for a living organism, DNS is the blueprint for the network. Whether that's your company's network or the internet, it doesn't matter.
And just as DNA naturally changes over time and in response to outside influences impacting it — so does DNS. Servers get moved. IP addresses get reassigned. (We don't have many of those, at least the v4 types. And IPv6 is, sadly, still a mystery to most network environments. Maybe we should bring in Guru Saj.) Domains get restructured, expanded or shrunk, merged or split.
DNS is a mission-critical system. Without it, there's no email. (MX records!) No web browsing. (A/AAA records!) No streaming music on Spotify. (They do some really creative stuff with their DNS.) No 4G/5G. (DNS is instrumental in enabling the proper routing for many of the largest mobile operators.) Quite simply, without DNS, there's no internet as we know it.
Our world is critically dependent on thousands or millions of networks working smoothly on their own as well as with each other. In turn, those networks are critically dependent on DNS to make that possible.
Besides making DNS more manageable with our products and understandable with our training courses, we at Men&Mice are passionate about sharing knowledge about the technologies we work with. We're building an extensive knowledge base to cover DNS, DHCP, and IPAM in detail — from 'What is DNS?' to 'How do I execute a KSK roll on my DNS?' — for you to peruse as you need.
We have 30 years' worth of experience in this space, but DNS use cases are endless, as demonstrated above. We'd like to invite you to ask whatever questions you want to be answered, and we'll make sure it has a place in our content. We also offer consulting for those who have a more pressing and specific business need for DNS information: we know what DNS can be and are happy to help you figure out what DNS should be to your company.