What Does DNS Actually Do?

Many people get confused when we talk about DNS the problem is that although it’s often discussed there are few explanations outside technical IT books. Anyway we found this great little video which helps explains the concept in easy to understand language which hopefully some people will find useful. If you’re interested in doing anything online from playing games to working with that VPN service then knowing the basics of DNS will certainly be helpful.

Transcript below:

Hi, there! In this video, you’ll learn about a crucial part of the Internet, the domain name system, or DNS. So, what is DNS? Well, it’s a translation system that allows us humans to search the Internet using language we’re comfortable with. Without DNS, the Internet as we know it would not exist. For example, you couldn’t do your shopping online; you’d have to drive to an actual store to buy your things. There’d be no way to stream music or videos to your smartphone, and no way to video chat with a friend across the ocean, or even across the street.

But what does DNS have to do with this? The Internet is made up of computers that are set up in large networks around the world. These networks are connected by a web of underground, and in some cases, undersea wires. Computers on the Internet communicate with each other using strings of numbers called Internet Protocol, or IP addresses. IP addresses function like street addresses; they identify where a computer is located on the Internet and help guide the information traveling between computers.

Now it’s one thing for computers to communicate using strings of numbers, but imagine if we humans had to memorize these seemingly random numbers strings, for every single website we wanted to find… not very realistic, huh? Well because of DNS, we don’t have to. DNS translates the human-friendly domain names that we’re comfortable using into the IP addresses that computers need to communicate with one another. When you type a domain name into your web browser, your browser and computer to determine if one of them already has the domain’s related IP address in their memory.

If it’s a domain that you’ve recently visited, like say a newspaper you look at every day, your browser may have stored the domain name and IP address in its memory and can display the website in a split second. If the domain isn’t found in local memory, your computer takes the search out to the Internet where it asks, or queries, a series of DNS servers if they have the domain name in their memory or a database.

The first DNS server that receives the query checks its memory for the domain name. If it doesn’t find the domain name in its memory, it sends the query on to the next DNS server to see if it can help. As soon as the domain name is found on a DNS server that the server returns the domain name and its IP address to the requesting DNS server and on down the line until it arrives back at your computer. Each time a requesting DNS server receives a domain name and IP address, the server stores the information in its memory, so any future requests for the domain name can be answered more quickly.

Once your computer has the IP address for the domain name, your browser knows where to find it on the Internet. Your browser uses your computer to communicate with the server where the domain name is hosted and requests any associated files. The host server returns the files, which then display in your web browser. Our ability to use domain names to quickly and easily retrieve websites and files from the Internet is entirely dependent on this tightly integrated and tiered line of communication. So the next time you buy a pair of shoes online, listen to some music on your smartphone, or video chat with a friend on another continent; remember, it’s not magic that lets you do these things on the web, it’s DNS! .

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