Type A URL Into The Address Bar


Type a URL in Address Bar

What happens when a user type a URL into the address bar of internet browser e.g. netscape, chrome. Perform a hit to fetch the webpage and after a while the corresponding webpage displayed.


Rationale : Some of the frequently used computer’s application might turn into the scenarios, which look very general, but it carries a lot of technical information e.g. browsing internet.


 Interviewer would like to understand Interviewees basics, thought process, approach to provide summarize answer for the given open ended scenario related to data communication.


Sample answer from a professional point of view

This scenario involves several types of technologies related to Client/Server architecture for data communication.

It talks about the overall flow of request/response, which includes various types of technical concepts e.g.

Protocols: DNS, HTTP, TCP/IP, ARP, Routing Protocols

Functional processing: Packaging a HTTP request, adding certain Protocol headers and writing it to lowest ethernet adapter to travel to destination.

In high level:

Client as an internet browser sends this webpage request to a web server by typing the URL at address bar and perform hit button.

  • Certain processing happens inside the browser application e.g. browser application verifies the correctness of types URL, browser approaches to appropriate DNS server to receive the IP address of typed URL as DNS response, browser prepare a HTTP get request and send to the web server.
  • Certain processing happens in the TCP/IP stack e.g. to send a get request to web server, client initiate a TCP connection to the Web server, IP protocol adds its header, ARP protocol find MAC address for corresponding next hope

Travelling this request from client machine to web server (assuming it’s located in other network), uses the depth of routing technologies e.g. if client machine located in korea and server located in United States, then this require to travel from various routers.

On arrival of this request at web server, It processed by the TCP/IP stack of that machine where web server is running. web-server prepares a response back to the client, which travels back to the client machine from where this request was originated.

I have explained this scenario in a high level flow; please let me know any specific step which I can explain detail e.g. step: How Internet browser issues a DNS query request and get a DNS response?, step: How ARP get corresponding MAC address ? , Step: How web-server parses received HTTP get request?, step: what happens if web-server send a reply and client didn’t received it ?

It also depends on the type of interview e.g. telephonic vs face-to-face, if it’s a face-to-face then it’s a good practice that a professional explains its answer while drawing a diagram on white-board or paper.

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Since last 15 years in different geographical locations, Sumit prepared hiring format for several hiring managers/teams to hire the balanced talents and interviewed talents on the various stages of their selection process. He also interviewed by hundreds of companies in different geographical locations.His best conclusion for hiring teams and candidate is to prepare in advance. Here ‘advance’ means keep your interview book ready and continue to update it even you are not going to interview candidates or applying for any job in next six months.