Tech Terms Explained: What is DNS?

We done occasional articles where we define tech terms for you. We explained Dark and Deep Web, Memory vs Hard Drive, Explained File Extensions, difference between Modem, Router, and Firewall, or even the difference between the variety of Intel processors or Solid-state versus Traditional Hard Drives. This month, we’re going to explain one of the critical underpinnings of how the Internet works: DNS.

First off, to understand why we need DNS, we need to explain a bit about how the internet works. Every device and service connected to the internet has an IP address of some sort. They’ll have an address like Even devices internal on your network that aren’t directly facing the public internet will have an IP address, usually something like 192.168.1.X or 10.0.100.x or something similar. So if you want to connect to a service or computer online, you could connect directly to that IP address and go on your way.

However, remembering a bunch of numbers is a pain. That’s where DNS comes in.

DNS stands for Domain Name System. Basically, consider DNS the Internet’s phone book. Some of us above a certain age remember phone books (but for you young folks, it’s your SmartPhone’s contact list). You didn’t necessarily know a person’s phone number, but you knew who you wanted to get in touch with. You don’t want to have to memorize a pile of numbers (IP addresses, in this case) to get to the website you’re looking. So you’d look them up by name and then call their number.

This is where DNS comes in. Thanks to DNS, you can type a domain like into the address bar of your browser and go to that website instead of typing into your browser.

So how does it work? That’s where it all gets a bit complicated. There are a variety of ways that your operating system and browser can pull IP addresses for the domain names your system is trying to find (and it all happens transparently in the backend). This quick video and this colorful comic explain it very well:

Basically, your request keeps going up the chain of system services, caches, resolvers and servers on the Internet until one of them delivers a valid IP address answer to get to your domain. And this all happens very quickly and can happen dozens of times when you load a single webpage (as content on websites are frequently pulled from multiple servers and domains).

Obviously, there is a lot more to it than that, but that’s the basic gist of it.

Because of the Internet’s heavy reliance on DNS, you want to make sure the answers you get back for IP addresses are correct and that they’re not going to redirect you to a malware-infested Website. Which is why we install OpenDNS protection with all our CompleteCare clients to help make sure DNS requests are filtered and blocked if necessary.

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