DNS (Domain Name System):

  • DNS is a distributed database system that translates hostnames to IP addresses and IP addresses to hostnames.
  • The domain name system (DNS) is a naming database in which internet domain names are located and translated into internet protocol (IP) addresses. 
  • The domain name system maps the name people use to locate a website to the IP address that a computer uses to locate a website. 
  • For example, if someone types google.com into a web browser, a server behind the scenes will map that name to the corresponding IP address, something similar in structure to 121.12.12.121.

  • When DNS was not into existence, one had to download a Host file containing host names and their corresponding IP address.
  • But with increase in number of hosts of internet, the size of host file also increased.
  • This resulted in increased traffic on downloading this file. To solve this problem the DNS system was introduced.
  • The following table shows the Generic Top-Level Domain names:

  • The following table shows the Country top-level domain names:


DNS Working:

  • DNS translates the domain name into IP address automatically.
  • Following steps will take you through the steps included in domain resolution process:
  1. When we type www.tutorialspoint.com into the browser, it asks the local DNS Server for its IP address. Here the local DNS is at ISP end.
  2. When the local DNS does not find the IP address of requested domain name, it forwards the request to the root DNS server and again enquires about IP address of it.
  3. The root DNS server replies with delegation that I do not know the IP address of www.tutorialspoint.com but know the IP address of DNS Server.
  4. The local DNS server then asks the com DNS Server the same question.
  5. The com DNS Server replies the same that it does not know the IP address of www.tutorialspont.com but knows the address of tutorialspoint.com.
  6. Then the local DNS asks the tutorialspoint.com DNS server the same question.
  7. Then tutorialspoint.com DNS server replies with IP address of www.tutorialspoint.com.
  8. Now, the local DNS sends the IP address of www.tutorialspoint.com to the computer that sends the request.