DNS is one of the essential part of Internet Infrastructure. With the help DNS, you can connect with any website without knowing it’s IP address. It is difficult to remember IP address for websites. It is in number like 199.239.x.x and numbers are not easy to remember for many websites. That’s because DNS is the phone book that translates names such as www.techiescure.com to Internet protocol (IP) addresses such as 199.239.x.x, and vice versa. DNS saves us from having to remember the IP addresses of all of our favorite sites, and it allows web pages to link to others by name, not by IP address.
What is recursive DNS Server?
Let’s take an example when you making a request to a website from your browser, the host computer will then make a request to recursive DNS server to find the IP address associated with the website; this is assuming your OS and web browser do not already have a response cached. From there, the recursive server will check to see if it has a cached DNS record from an authoritative name server, and still has a valid time-to-live (TTL). If the recursive server does not have the DNS record cached, it begins the recursive process of going through the authoritative DNS hierarchy.
(Recursive DNS provides recursive DNS. something which repeats or refers back to itself)
Authoritative DNS name server?
Authoritative DNS name-servers are responsible to provide answer to recursive DNS name-server with the IP “mapping” of the intended website. The authoritative nameserver’s responses to the recursive name-servers contain important information for each domain, such as corresponding IP addresses and other essential DNS records.
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to understand better let’s put both together, Finally let’s take another example to make it simple, suppose that you want to search a picture of a bird, so you type www.google.com into your web browser to go google search page. However your computer does not know where the server for www.google.com is located, so your computer sends a query to recursive DNS name-server (Open DNS) to locate the IP address of the website for you. The recursive DNS name-server is now assigned the task of finding the IP address of the website you are searching for. If the recursive DNS record cached in its system, it will then query the authoritative DNS hierarchy to get the answer.
