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What is DNS?

What is DNS?
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DNS means ‘Domain Name System’, and it one of the main reasons internet exists today. It’s one of the most important part of the World Wide Web. It’s a technology that let users resolve domain names into a matching IP address where the website that we want to access is actually stored. Today you will learn more about what is DNS and why it plays such a crucial role in the way internet works.

What is DNS? Why is it so important?

When a computer is connected to a network (Internet or a local area network – LAN), it always has an IP address assigned. When you are connected over a small network, it’s easy to memorise all IP addresses for each one of the computers, however imagine for a second what would it be to know a network with millions of devices (smartphones, tablets, computers, servers, VoIP devices, etc) each one with a different IP address. See? It’s impossible to know each one of them, that’s why domain names exist and the purpose of the DNS servers is to translate IP address into easy to remember domain names / host names.

Having said that, now you know that the domain system is the all mighty service that is used to translate network names (IP addresses) into domain names.

How does DNS works?

The DNS have two important parts:

DNS Client: this is us, when we work on a computer, each operating system has its own dns client, that is the one in charge of requesting the domain name resolution to the dns servers.

DNS Server: are the ones who answer the requests made by the DNS clients. There are lot of DNS servers, you will usually work with the DNS servers provided by your ISP (Internet service provider), however, you can also use free public dns servers like the ones provided by Google: 8.8.8.8 and 8.8.4.4.

What’s my DNS?

That’s another important question made by lot of users, specially the ones that work with web hosting providers.

When you sign up for a web hosting plan on a web hosting provider, they will give you two or four Name Servers servers to use, for example:

ns1.yourprovider.com
ns2.yourprovider.com

This two Name Servers are part of the DNS server of your hosting provider. When you use those NS in your domain name registrar, then your domain is able to resolve to the server where your website is hosted.

How can I find out what is my DNS?

To know your DNS servers, you can use online tools like this dns checker, that will give you a quick review of your dns health check, including your main DNS servers.

You can also use terminal based tools like whois command to know the DNS servers of any domain name, for example:

whois nixcp.com | grep name -i

The output should look similar to this:

[webtech@localhost ~]$ whois nixcp.com | grep name -i
Domain Name: CPANELTIPS.COM
Registrant Name: Esteban Borges
Admin Name: Esteban Borges
Tech Name: Esteban Borges
Name Server: ns0.dnsmadeeasy.com
Name Server: ns2.dnsmadeeasy.com
Name Server: ns3.dnsmadeeasy.com
Name Server: ns4.dnsmadeeasy.com
domain name registration record. We make this information available "as is",
[webtech@localhost ~]$

As you see in there, at cPaneltips.com we use four DNS servers from dnsmadeeasy.com, our DNS server provider.

You can also use online tools like ICANN Whois to get your current DNS.

About the Author: Esteban Borges

Experienced Sr. Linux SysAdmin and Web Technologist, passionate about building tools, automating processes, fixing server issues, troubleshooting, securing and optimizing high traffic websites.