What is DNS?
In the Internet Computers always identify each other with unique numbers called IP addresses they do not understand human languages if computers do not understand human languages how they load a website when we type its address in the web browser’s URL Bar that’s the place where DNS comes in suppose we speak English and we want to communicate a person who speaks French for effective communication we will need a translator same is the case on the Internet to computers or web browsers understand IP addresses and we humans understand our languages say English DNS acts as a translator between humans and computers.
DNS or domain name system maintains a table where names are mapped into numbers or more specifically where websites domain names are mapped to their IP addresses now when we type akhileshmittal.in. The web browser DNS translates it to the web browsers language that is IP address and gives it to the web browser now web browser understands that we want to access akhilehmittal.in so it contacts the akhileshmittal.in hosting server and loads akhilehmittal.in on the computer ensure DNS acts as a phonebook of the Internet via computer searches with names to get numbers.
How DNS works internally?
We should know what our DNS servers, servers are computers storing HTML files images, sounds, videos for any other file types servers that work together to provide IP address of the requested website to the web browser are called DNS servers.
There are four types of DNS servers
- DNS recursive resolver
- DNS resolver root name server top-level domain
- TLD name server
- Authoritative name server
DNS recursive resolver
DNS resolver is provided by the Internet service provider it connects the web browser of our computer to the DNS name servers.
DNS resolver root name server top-level domain
There are 13 sets of root name servers logically named as letter.root- servers.net where letter ranges from ‘a’ to ‘m’ and are operated by 12different organizations each set has a number of servers placed around the world and informational page exists for all. Root name servers at address letter.root- servers.org where letter ranges from a’ to ‘m’ except ‘g’ for ‘g’ this is the homepage address details of all root name servers can be found in the website www.akhileshmittal.in server stores the information of all domains sharing a common domain extension for example.com.
TLD name server
TLD name servers stores the information of all web sites ending with .com extension .net TLD name server stores information of all .net web sites.
Authoritative name server
The last server in the domain name system it stores the IP address of the requested web site authoritative name server for a website can be found with these CMD commands.
Open CMD and type ns lookup hit enter set query equals NS and hit enter then type the domain name hit enter you will be able to see the authoritative name servers one is master and the other is slave, slave is the exact replica of master and is used to share the DNS server load.
How a computer loads a website
We type www.facebook.com in the web browser since web browser needs IP address so it forwards the query to the computer’s operating system. Operating systems are configured to forwards what the query to the DNS resolver operating system then contacts the DNS resolver DNS resolver checks its cache whether it has the IP address of the requested website if not DNS query is forwarded to the root name servers root name server checks the extension of the website whether it is .com, .in, .org, .net etc based on the extension the root name server provides the IP address of TLD name server to the DNS resolver in this case IP address of .com TLD name server is provided to the DNS resolver DNS resolver then contacts .com TLD name server which then provides the IP address of the authoritative name server which should necessarily store the IP address of the requested website finally the authoritative name server provides the exact IP address of facebook.com to the DNS resolve work DNS resolver stores this information in its cache for future use and provides the IP address to the computer’s operating system operating system then forwards it to the web browser the web browser then contacts the Facebook server and loads the requested website that is www.facebook.com.
But how TLD names of a nose which authoritative name server stores the IP address of the requested website it all begins when we purchase a domain name from a registrar for example go today in registrar’s website we can set the authoritative name server that domain should use we get the details of authoritative name server when we buy a web hosting plan from companies like hostinger hoting company once authoritative name server details are entered in the registrar’s website the Registrar tells the TLD name servers managing authority registry to update the TLD name server with the details of authoritative name server the user has provided so now TLD names of a nose which authoritative name server will provide the exact IP address of the requester web site.
Is DNS necessary?
If we know the dedicated IP address of the website we can access it simply by typing its IP address in the web browser in such cases DNS will not play any role because we already know the IP address of the website however as the number of websites increases it becomes difficult to remember the IP addresses so DNS servers eliminate the need for humans to memorize these complex IP addresses the only thing we need to memorize is the domain names.