What is Domain Name System (DNS) ?

Domain Name System is a fantastic technology that helps us open internet addresses without a hustle. We quickly write the domain name and the DNS has the job to find the IP of the domain we wrote. Similar to the phone book on your smartphone. When you need to find Srikanta, you write “Srikanta,” and you don’t need to remember his actual number.

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DNS is a necessary part of the Internet. It translates all the inquiries into IP addresses, and it can identify different devices that are connected to the network.

How does the Domain Name System (DNS) work?

When you visit a domain name such as techblog.tips, your computer follows few of steps to turn the human-readable Internet address into an IP address. This happens whenever you use a domain name to browse websites, sending an email or listening to Internet radio stations.

Now here is how DNS server works with one example:

Step 1: Request information

The process begins when you ask your computer to resolve a domain name, such as visiting http://techblog.tips. At first your computer looks local DNS cache, which stores information about IP address that your computer has recently retrieved.

If your computer doesn’t already know the answer, it needs to perform a DNS query to find out.

Step 2: Ask the recursive DNS servers

If the information is not stored locally, your computer queries (contacts) your ISP’s recursive DNS servers. These specialized computers perform the legwork of a DNS query on your behalf. Recursive servers have their own caches, so the process usually ends here, and the information is returned to the user computer.

Step 3: Ask the root nameservers

If the recursive servers don’t have the answer, they query the root nameservers. A nameserver is a computer that answers questions about domain names, such as IP addresses. The thirteen root nameservers act as a kind of telephone switchboard for DNS. They don’t know the answer, but they can direct our query to someone that knows where to find it.

Step 4: Ask to the TLD name servers

The main name servers will look at the first part of our request, reading from right to left www.techblog.tips and direct our query to the Top-Level Domain (TLD) name server for .tips. Each TLD, such as .com, .org, and .tips, have their own set of nameservers, which act as a receptionist for each TLD. These TLD servers don’t have the information that we need, but they can refer us directly to the servers that do have the information that we need.

Step 5: Ask the authoritative DNS servers

The nameservers review the next part of our request from techblog.tips. and direct our query to the nameservers responsible for this specific domain. These authoritative name servers are responsible for knowing all the information about a particular domain, which is stored in DNS records. There are many types of DNS records, which each contain a different kind of information. In this example, we want to know the IP address for www.techblog.tips, so we ask the authoritative nameserver for the Address Record (A).

Step 6: Retrieve the record from the server

The recursive server retrieves the A record for techblog.tips from the reliable name server and stores the record in its local cache. If anyone else requests the host record for techblog.tips, the recursive servers will already have the records and will not need to go through the lookup process again. All records have a time-to-live value, which is like an expiration date. After a while, the recursive server will need to ask for a new copy of the record to make sure the information doesn’t become out-of-date.

Step 7: Receive the answer

The recursive server returns the A record to your computer. Your computer stores all records in its cache and reads the IP address from the record, then send this information to your browser. The browser then opens a connection between the web server and browser then receives the website.

This entire process takes only a few milliseconds to complete.

Thanks for reading this article, I hope it will help you to understand more about the Domain Name System (DNS). For more articles like this, follow our blog regularly.

Source: DYN

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One comment

  1. Hell yeah

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