DNS stands for Domain Name System. Generally domain names are in alphabet format but that cannot be read by a machine. The DNS converts the domain names into machine readable IP addresses. DNS automatically converts the domain names that we enter in the browser into IP addresses.
Importance of domain name system
Domain name system works like a phone book. Thus, when you want to know a person number, you can refer phone book with that person name. Likewise, the DNS is working for the Internet. If you want to visit a website, you will have to type the domain name of the site. Assume the site you are looking for doesn’t have a DNS. In such a case, you need to search with the IP address of that particular website. It is not easy to do so. The DNS will help at that time.
How does DNS work?
When you enter a domain name in a web browser, your computer will follow a few steps to convert the characters (letters) into machine readable language that is the IP address, and involves the following steps:
Request for information
When you enter a domain name in the browser, the process starts. First, your computer checks it in local DNS cache. This is to verify that it is recently retrieved or not. If it not found, then it sends a DNS request that is DNS query to perform.
Asking the recursive DNS server
If the domain name is not found in locally, your computer takes the help of ISP’s recursive DNS server. Here, special computers are looking in its cache to know about the details and it gives the results to the user.
Asking the root name servers
If it is not found in the recursive DNS server, the computer takes the help of root name servers. Name servers are the ones having all the information about domain names and IP addresses. If they don’t get the answer as well, they query a server who knows to find it out.
Retrieve the record
The recursive server gets the information about your search for site through authoritative name servers. And, it stores all the information in its local cache for future purpose.
Receiving the answer
Recursive server sends the information to your computer. Then your computer stores a copy of that record and it will send the information to browser. Again browser is going to connect a web server and opens the website which you are looking for.
The whole process total process takes only a few milliseconds.