[SOLVED] CS 457 – Fall 2015 Homework 5

CS 457 – Fall 2015 Homework 5

Date due: Tuesday, November 3, 2015 by 2PM

Note: This homework is ESSENTIAL if you want to successfully complete project 3. If you cannot do this assignment by hand, you will not be able to do it programmatically.

BE CAREFUL: the “dig” command issues a DNS query on port 53. Unfortunately, CSU hijacks port 53 to its own DNS resolver, and you want to issue queries directly to external authority nameservers. You will need to run this from an external site that allows port 53, or from the netsec computers, or from home. Just be sure to check if the server that answers is the server that was queried.

Problem 1 (25 points total):

Use iterative DIG commands to the appropriate DNS NAMESERVERS (authority servers) in order to resolve the domain name www.cnn.com into A record(s) starting from the root server. Use the format:

dig @x.y.z.w www.cnn.com
The “@x.y.z.w” informs dig which nameserver is to receive the query.

You will need to execute this command approximately 10 times in order to resolve the domain name. A CNAME chase is involved. You will get 2 points for each DIG, up to 10 digs. You will get 5 extra points for the final name resolution.

Just to get you started, the A root server is located at IP address 198.41.0.4, but you would want to verify that by doing a “dig .” and following the delegation.

Your first dig will be
dig @198.41.0.4 www.cnn.com

The rest is up to you.
NOTE: ALL of your DIG’s must use the @x.y.z.w (IP address) format. Do not use a domain name here,

even though a domain name would work (e.g. [email protected]).

Perform this task in a terminal window, then copy and paste the entire series of digs into a text editor and submit this as a PDF to CANVAS.