What is DNS? How does DNS to IP conversation work?

Every day we use the internet, visits websites, and checking our email. But, it's a fact that most of the people really don't know how operating system converts a hostname into IP address or what happens when they type https://www.google.com in their browser. In order to help you understand better, we are going to discuss DNS and how DNS to IP conversation works.

So, let's find out what is DSN?

The Domain Name System (DNS) (use since 1985) is a hierarchical decentralized naming system for computers, services, or other resources connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. Most prominently, it translates more readily memorized domain names to the numerical IP addresses needed for locating and identifying computer services and devices with the underlying network protocols. By providing a worldwide, distributed directory service, the Domain Name System is an essential component of the functionality on the Internet.

4 DNS servers involved in loading a webpage

1. DNS recursor

The recursor can be thought of as a librarian who is asked to go find a particular book somewhere in a library. The DNS recursor is a server designed to receive queries from client machines through applications such as web browsers. The recursor is then responsible for making additional requests in order to satisfy the client’s DNS query.

2. Root name server

The root server is the first step in translating human-readable host names into IP addresses. It can be thought of like an index in a library that points to different racks of books - typically it serves as a reference to other more specific locations.

3. TLD name server

The top level domain server (TLD) can be thought of as a specific rack of books in a library. This nameserver is the next step in the search for a specific IP address, and it hosts the last portion of a hostname. In example.com, the TLD server is "com".

4. Authoritative nameserver

This final nameserver can be thought of as a dictionary on a rack of books, in which a specific name can be translated into its definition. The authoritative name server is the last stop in the nameserver query. If the authoritative name server has access to the requested record, it will return the IP address for the requested hostname back to the DNS Recursor that made the initial request.

Domain names are the human-readable website addresses we use every day. For example, Google’s domain name is google.com. If you want to visit Google, you just need to enter google.com into your web browser’s address bar. But, your computer doesn’t understand where "google.com" is. Behind the scenes, the Internet and other networks use numerical IP addresses.

Let's find step by step how does DNS to IP conversation work?

• A user types ‘example.com’ into a web browser and the query travels into the Internet and is received by a DNS recursive resolver.

• The resolver then queries a DNS root name server (.).

• The root server then responds to the resolver with the address of a Top Level Domain (TLD) DNS server (such as .com or .net), which stores the information for its domains. When searching for example.com, our request is pointed toward the .com TLD.

• The resolver then makes a request to the .com TLD.

• The TLD server then responds with the IP address of the domain’s name server, example.com.

• Lastly, the recursive resolver sends a query to the domain’s nameserver.

• The IP address for geekboots.com is then returned to the resolver from the nameserver.

• The DNS resolver then responds to the web browser with the IP address of the domain requested initially.

• The browser makes a HTTP request to the IP address.

• The server at that IP returns the webpage to be rendered in the browser.

 

As you can see from this description, DNS is a rather amazing distributed database. It handles billions of requests for billions of names every day through a network of millions of name servers administered by millions of people. Every time you send an e-mail message or view a URL, you are making requests to multiple name servers scattered all over the globe. The process is usually completely invisible and extremely reliable.