Description

Exercise 3: Digging into DNS (marked, include in the lab report)
In order to answer the following questions, you will make DNS queries using some of the query types you have encountered in the above exercise. Some questions require you to make multiple DNS queries. Before you proceed, read the manpage of dig (type man dig in the terminal). Make sure you understand how you can explicitly specify the following:
• nameserver to query
• type of DNS query to make (the default query types are those you saw in exercise 1)
• performing reverse queries
Note: Include the output of all the dig commands you have used in your answers.
To send a query to a particular name server (say x.x.x.x) you should use the following command:
dig @x.x.x.x hostname
Question 1. What is the IP address of www.eecs.berkeley.edu . What type of DNS query is sent to get this answer?
Answer:

23.185.0.1 Type A
Question 2. What is the canonical name for the eecs.berkeley web server? Suggest a reason for having an alias for this server.
Answer:
live-eecs.pantheonsite.io. and fe1.edge.pantheon.io.
canonical name often is difficult to remember. Alias like www.eecs.berkeley.edu is easier to remember. And it can be useful to run multiple services with different domain name but same IP.

Question 3. What can you make of the rest of the response (i.e. the details available in the Authority and Additional sections)?
Answer:
The Authority section contain the four authoritative name servers record for edge.pantheon.io.
The Additional section contain the IP address of four authoritative name servers

Question 4. What is the IP address of the local nameserver for your machine?
Answer:
129.94.242.2(from bottom of output) local DNS server for CSE network.

Question 5. What are the DNS nameservers for the “ www.eecs.berkeley.edu .” domain (note: the domain name is eecs.berkeley.edu and not www.eecs.berkeley.edu )? Find out their IP addresses? What type of DNS query is sent to obtain this information?
Answer:

The DNS nameservers are IP IPV6 ns.eecs.berkeley.edu. 169.229.60.153 adns2.berkeley.edu. 128.32.136.14 2607:f140:ffff:fffe::e adns1.berkeley.edu. 128.32.136.3 2607:f140:ffff:fffe::3 ns.CS.berkeley.edu. 169.229.60.61 adns3.berkeley.edu. 192.107.102.142 2607:f140:a000:d::abc
NS query.

Question 6. What is the DNS name associated with the IP address 111.68.101.54? What type of DNS query is sent to obtain this information?
Answer:

webserver.seecs.nust.edu.pk. PTR

Question 7. Run dig and query the CSE nameserver (129.94.242.33) for the mail servers for Yahoo! Mail (again the domain name is yahoo.com, not www.yahoo.com ). Did you get an authoritative answer? Why? (HINT: Just because a response contains information in the authoritative part of the DNS response message does not mean it came from an authoritative name server. You should examine the flags in the response to determine the answer) Answer:

There is not an authoritative answer. There is no AA flag. CSE nameserver has no authority on yahoo domain.

Question 8. Repeat the above (i.e. Question 7) but use one of the nameservers obtained in Question 5. What is the result?
Answer:

The status is REFUSED. 0 answer. No aa flag.

Question 9. Obtain the authoritative answer for the mail servers for Yahoo! mail. What type of DNS query is sent to obtain this information?
Answer:

dig @ns1.yahoo.com yahoo.com MX
Use one of authoritative nameservers from q7(ns1.yahoo.com) which is authoritative nameservers from yahoo domain. There is aa flag.
Question 10. In this exercise you simulate the iterative DNS query process to find the IP address of your machine (e.g. lyre00.cse.unsw.edu.au). First, find the name server (query type NS) of the “.” domain (root domain). Query this nameserver to find the authoritative name server for the “au.” domain. Query this second server to find the authoritative nameserver for the “edu.au.” domain. Now query this nameserver to find the authoritative nameserver for “unsw.edu.au”. Next query the nameserver of unsw.edu.au to find the authoritative name server of cse.unsw.edu.au. Now query the nameserver of cse.unsw.edu.au to find the IP address of your host. How many DNS servers do you have to query to get the authoritative answer?
Answer:
dig . NS

dig @a.root-servers.net. au. NS

dig @m.au. edu.au. NS

dig @q.au. unsw.edu.au NS

dig @ns1.unsw.edu.au cse.unsw.edu.au. NS

Our IP
dig @maestro.orchestra.cse.unsw.edu.au. vx2.orchestra.cse.unsw.EDU.AU A

For lyre00.cse.unsw.edu.au dig @maestro.orchestra.cse.unsw.edu.au. lyre00.cse.unsw.edu.au A

5 DNS servers : a.root-servers.net. m.au. q.au. ns1.unsw.edu.au maestro.orchestra.cse.unsw.edu.au. The IP of our machine is 129.94.242.115 lyre00.cse.unsw.edu.au is 129.94.210.20

Question 11. Can one physical machine have several names and/or IP addresses associated with it?
Answer:
Yes. A machine can have many names and IP addresses associated with it. And IP address can have multiple names(aliases).

EXERCISE5 (PYTHON3.7.3 CSE MACHINE)