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Tribhuvan university > CSIT - 2065 Syllabus > Web Technologies > Old Questions > 2068-II

Web Technologies - Old Questions

Syllabus Notes Old Questions Unit Wise Questions Question Bank

11.  Explain briefly, how the domain names are translated to IP addresses.

5 marks | Asked in 2068-II
DNS (Domain Name System) is what translate domain name (for eg. www.google.com) into an IP address that our browser can use (for eg. 173.194.35.148). Before the page is loaded, the DNS must be resolved so the browser can establish a TCP connection to make the HTTP request. The DNS Resolution process starts when the user types a URL address on the browser and hits Enter.

The DNS works as follows:
  1. A user types ‘example.com’ into a web browser and the query travels into the Internet and is received by a DNS recursive resolver.
  2. The resolver then queries a DNS root nameserver (.).
  3. The root server then responds to the resolver with the address of a Top Level Domain (TLD) DNS server (such as .com or .net), which stores the information for its domains. When searching for example.com, our request is pointed toward the .com TLD.
  4. The resolver then makes a request to the .com TLD.
  5. The TLD server then responds with the IP address of the domain’s nameserver, example.com.
  6. Lastly, the recursive resolver sends a query to the domain’s nameserver.
  7. The IP address for example.com is then returned to the resolver from the nameserver.
  8. The DNS resolver then responds to the web browser with the IP address of the domain requested initially.

    9. Once the 8 steps of the DNS lookup have returned the IP address for example.com, the browser is able to make the request for the web page:

  9. The browser makes a HTTP request to the IP address.
  10. The server at that IP returns the webpage to be rendered in the browser (step 10).