The computer science department at Purdue University chose t

The computer science department at Purdue University chose to place the following type A resource record entry in its domain name server:

Localhost.cs.purdue.edu 127.0.0.1

Explain what will happen if a remote site tries to ping a machine with domain name localhost.cs.purdue.edu? Explain the process of name resolution and the result of the ping command/response.

Solution

Name Resolution

1. When the request is sent through the browser, the local resolution server is invoked and the request is send to the local server, the local server checks its cache , if the name matches the same is sent to the browser if not it checks the static mapping in its host file and if it matches the mapping is returned to the browser , lets say its not
2. The local resolver creates a recursive query and sent the request to the local DNS . The local DNS checks its cache if not the checks whether the request is in the same domain or same zone . if not
3.The local DNS generates a request and send it to the root name server , it resolves and send the name (Here its .edu)
4. Then again the local DNS send its to .edu and the name server of .edu returns the name and address of the name server for purdue.edu
5. purdue.edu checks its resource records and returns the name server of cs.purdue.edu
6. the local DNS sends the request to cs.purdue.edu, and it returns the ip address of host to local DNS and then local DNS sens it to browser.