CSE5344/4344 Assignment 1 – Computer Networks

CSE 5344/4344 Computer Networks

Summer 2023

Assignment 1

Instruction: For this homework, you can use multiple resources and you can discuss with your classmates, but you must answer each question in your own words. If anything is found copied, everyone involved will be penalized -100. You must submit your answer in pdf format.

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Objective: An introduction to the packet analyzer (Wireshark). ***Support all your answers with respective screenshots from WireShark. Show as much details as possible to demonstrate the concepts.

1. Find a situation in which you may use Wireshark to observe or track protocols as they are being used while engaging with a network application of your choice. Write a brief report that details, step by step, how Wireshark is being used to examine or follow protocols.

2. Briefly explain UDP network protocol. Demonstrate a comparison (similarity/dissimilarity if any) of the protocol as learned from the textbook with the Wireshark output.

3. Using Wireshark to demonstrate TCP three-way handshake.

 4. Go to vbsca.ca/login/login.asp. Type ‘yourName123’ as both username and password and submit [replace yourName with your last name]. This is a website where the password is unencrypted. Provide a screenshot of WireShark showing the unencrypted password.

5. Click the following URL http://gaia.cs.umass.edu/ethereal-labs/INTRO-ethereal-file1.html. To load the above page, what version of HTTP is the server using? Provide screenshot using for both the browser and Wireshark.

6. What is the Internet address of the utd.edu? What is the Internet address of your computer?

7. Click the following URL http://gaia.cs.umass.edu/ethereal-labs/INTRO-ethereal-file1.html Check if this file was modified. If yes? Then mention the date and time. Hint: IF-MODIFIED-SINCE

DNS:

 Capture DNS packets that are generated during web-surfing activity.

? Use ipconfig to empty the DNS cache in your host.

? Open your browser and empty your browser cache.

? Open Wireshark and enter “ip.addr == your_IP_address” into the filter, where you obtain your_IP_address with ipconfig. This filter removes all packets that neither originate nor are destined to your host.

 ? Start packet capture in Wireshark.

? With your browser, visit the Web page: http://uta.edu/ ? Stop packet capture.

Answer the following questions (include Wireshark screenshot for each):

 8. Briefly explain the function of DNS? Locate the DNS query and response messages. Are then sent over UDP or TCP? Provide a screenshot of Wireshark that includes the Source Port and Destination port for the DNS queried message.

9. What are Authoritative and Non-Authoritative name servers? Demonstrate one of them using WireShark.

10. What are the different types of DNS records? Using Wireshark examine the DNS query message and write the “TYPE” of the DNS record. Does the query message contain any “answers”?