DNS or The Domain Name Server is used to resolve human-readable host names like – www.facebook.com into machine-readable IP addresses like 31.13.65.36
Why is it important?
It is important because words are easy for people to remember and read, and computers use IP addresses to access websites.
If you want to visit www.facebook.com in a browser (Chrome or any other browser), your computer will use DNS to find the IP address of the website i.e, 103.21.59.149. In fact, without DNS, you will be able to visit our website (any website) by visiting the IP address directly, such as http://31.13.65.36
How does DNS Work?
When you try to visit a website domain, your machine will perform a series of steps to translate a domain name into a machine-readable IP address.
- Requests information from the local DNS cache on your computer, which is the data that your computer has newly retrieved.
- If the data is not cached locally, the machine will communicate with ISP’s DNS servers.
- If the data is not on the ISP’s DNS servers, the machine starts by querying the translation to the root name server. There are 13 root servers, and they are the entry points of the DNS protocol, but when they receive the request, they usually don’t know the answer (as there are many domain names) but they know who to ask.
- Root servers redirect you to a TLD (Top Level Domain) server. There are two types, these are generic TLDs (.com, .net, .edu etc.) and country code TLDs (.in, .au etc.).
- If the TLD server does not have an answer, it redirects you to the authoritative servers, these are nameservers where your domain name is registered.
- The ISP recursive server retrieves records for the domain from the authoritative nameservers and stores the records in the local cache.
- The ISP recursive server then returns the A record back to your computer, and your machine stores it in cache.
To know more about DNS and how does it work, visit here https://www.verisign.com/en_US/website-presence/online/how-dns-works/index.xhtml
