{"id":1094,"date":"2021-03-17T14:21:03","date_gmt":"2021-03-17T12:21:03","guid":{"rendered":"https:\/\/www.scalahosting.com\/kb\/?p=1094"},"modified":"2022-10-12T10:51:43","modified_gmt":"2022-10-12T07:51:43","slug":"what-is-dns","status":"publish","type":"post","link":"https:\/\/www.scalahosting.com\/kb\/what-is-dns\/","title":{"rendered":"What is DNS?"},"content":{"rendered":"

Ever tried to visit a website only to see \u201cthis site can’t be reached?\u201d<\/span><\/i>\u00a0<\/span><\/p>\n

That\u2019s a DNS error page. It means <\/span>your browser couldn\u2019t find the Internet Protocol<\/b> (IP) address for that website. It\u2019s a similar response to when you\u2019re calling a number, and it comes up as \u201cunavailable.\u201d<\/span><\/p>\n

\"What<\/span><\/p>\n

Think of DNS as an \u201cinternet directory,\u201d with IP addresses as numbers and domain names as actual names. In 2020, <\/span>Verisign listed over 300 million domain names.\u00a0 Although, this wasn\u2019t the case some 40 years ago. <\/span>Paul Mockapetris developed the DNS system in 1983<\/b> and dubbed it the Domain Name System (DNS).\u00a0<\/span><\/p>\n

\"What<\/span><\/p>\n

Screenshot: Paul Mockapetris<\/span><\/i><\/p>\n

Back then, computers could only communicate using numbers, which were not easy to remember.<\/span><\/p>\n

With time, <\/span>it became difficult to maintain and correspond specific addresses<\/b> with specific computers, hence the DNS. In this article, we’ll take a look at the DNS and how it operates.\u00a0<\/span><\/p>\n

How the DNS works with an Example<\/b><\/h2>\n

The DNS directory matches names to numbers<\/b>. It does this through the help of multiple DNS servers around the world.<\/span><\/p>\n

\"What<\/span><\/p>\n

Image Credit: SEObility<\/span><\/i><\/p>\n

These servers <\/span>store DNS records<\/b> that are domain names and <\/span>link them to a specific IP address<\/b> as soon as there is a query. You may also refer to these name servers as root servers. They store records of every domain name according to the location of the Top-Level Domain (TLD)<\/span><\/p>\n

TLDs are domain extensions<\/b>. You can find them at the end of your domain name as a two, three, or four-word character.<\/span><\/p>\n

Let’s put this into perspective using an example.\u00a0 Say you search for<\/span> www.scalahosting.com<\/span><\/i> on the internet. Your computer sends queries to multiple DNS servers that get the IP address before loading a web page.<\/span><\/p>\n

\"What<\/span><\/p>\n

Screenshot: Scala Hosting IP Address<\/span><\/i><\/p>\n

This query goes through four \u201c<\/span>authoritative name servers<\/span><\/i>\u201d that enable the DNS to function.\u00a0<\/span><\/p>\n

You might find all this difficult to understand, but hang on we\u2019ll talk about them in a minute.<\/span><\/p>\n

DNS (Recursive) Resolver<\/b><\/h3>\n

The DNS or recursive resolver <\/span>receives DNS queries<\/b> from your web browser or other web applications. The recursive resolver receives the hostname, which is the website and tracks down its IP address in the cache of your local device.<\/span><\/p>\n

Therefore to translate the hostname you queried, the DNS resolver will first figure out where the records of .com are, then scalahosting.com, and lastly, www.scalahosting.com.\u00a0<\/span><\/p>\n

This DNS server resolves the query immediately <\/b>when it finds the hostname. If not, it sends a query for the IP address of <\/span>.com<\/b> to an authoritative name server called DNS root server.\u00a0<\/span><\/p>\n

DNS Root Server<\/b><\/h3>\n

The root server is <\/span>the name server for the Domain Name System\u2019s root zone<\/b> (DNS).\u00a0<\/span><\/p>\n

It contains an up-to-date list of all global top-level domains (TLDs) in its servers. For each of these TLD, there\u2019s a matching numeric IP address of name servers with the TLD records on it.<\/span><\/p>\n

So, <\/span>the computer searches for the IP details of the TLD at the root server<\/b>, which is <\/span>.com<\/b> in this instance and sends it to the TLD name server to continue the process.<\/span><\/p>\n

Various organizations such as the University of Maryland, Verisign Inc, Cogent Communications, and the US Army Research Lab operate <\/span>13 root servers globally.<\/span><\/a> Computers access these root servers using 13 numeric IP addresses <\/span>to communicate from different locations.\u00a0<\/b><\/p>\n

Because of this, different local servers in one location <\/span>can share one IP address and communicate with multiple servers<\/b> in various locations using that location\u2019s root IP address.\u00a0\u00a0<\/span><\/p>\n

TLD Name Server<\/b><\/h3>\n

The TLD name server <\/span>contains specific DNS records<\/b> of the domain name and provides an authoritative name server\u2019s IP details.<\/span><\/p>\n

For this example, the TLD name server stores the IP address of Scala Hosting within the TLD name (.com). It then sends a specific IP address of the hostname to the DNS to continue the process.<\/span><\/p>\n

The Domain Name System (DNS) may find it challenging to function correctly in its absence because of the specificity.\u00a0<\/span><\/p>\n

Although the Internet Assigned Numbers Authority (IANA) and Internet Corporation for Assigned Names and Numbers (ICANN) recognizes three types of <\/span>TLD for different purposes:<\/b><\/p>\n