Have you ever wondered how computers communicate with one another? The internet allows computers to identify each other using a unique number called an IP address. They don’t understand the common language of human beings. How can they communicate with humans? DNS (Domain Name System), is what happens when we type a URL for any website in the search box. Because computers understand IP addresses, DNS acts as a translator between humans & computers. It maintains a table that maps the domain names of websites to their IP addresses. DNS interprets the URL to Google.com, so that it can be interpreted by the web browser. The web browser now recognizes that we wish to access google.com using the IP address to contact the server and connects us to the requested website.
DNS Servers work together to provide the IP address of the requested site to the web browser. There are four types of DNS Servers:
DNS Recursive Resolution/ DNS Resolver: DNS resolvers are issued by the Internet Service Provider. It establishes a link between our web browser and the DNS nameserver.
Root Name Server: There are 13 sets of root name servers logically named as letter.root-servers.net where letter ranges from ‘a’ to ‘m’ – g (g is the home page address) and are operated by 12 different organizations. Each set has several servers placed around the world, and an informational page exists for all root name servers at letter.root-servers.org.
Top-Level Domain/ TLD Name Server: The TLD name servers stores information about all domains that share a common extension (.com.in.net. etc. Exemple: The.com TLD server stores information about all websites with the.com extension.
Authoritative nameserver: This is the last server of the Domain Name System. It stores the IP address for the requested website. This command:nslookupset query=ns (domain name) can be used to find the Authoritative Name Server of a website.
What is DNS?
The IP address is required by the web browser to load the domain name. The DNS Resolver is a DNS Resolver. The DNS Resolver is then reached by the Operating System. The DNS Resolver checks its cache to confirm that it contains the IP address of the requested website. If it does not, the DNS query will be forwarded to root name server. Root name server checks whether the extension is.com,.net, or.org. The Root name server presents the TLD name servers’ IP address to DNS Resolver based upon the extension. The DNS Resolver then contacts the TLD name server for the requested extension. This server then provides the IP address of the Authoritative Name Server, which should store the requested website’s address. The Authoritative name server then provides the DNS resolver with the IP address for the requested website. DNS Resolver saves this information in its cache and provides the IP address of the operating system. The Operating System then forwards the information to the Web Browser. The Web Browser contacts the server and loads the website.
The question is how TLD determines which Authoritative server holds the requested website’s IP address. It all begins when you purchase a domain name from a Registry (or any other domain name provider). The Registrar’s website allows us to set the Authoritative Name Server the domain should use. When we purchase a web hosting plan, we are given the details of the Authoritative Name Server. Once the Authoritative server details have been entered in the Register, they will be activated.