CSCE 515: Computer Network Programming
Spring 2004
Homework 2
02/26/04
1. (2 points) A UDP datagram sent from source address 129.252.11.254 to destination
address 224.0.0.2 is as follows. What is the correct value for the UDP checksum of this
datagram? (You can use either hexadecimal or binary representation.)
07
00
00
0a
76
31
81
c1
1c
00
69
6c
31
fc
07
c1
?
08
0b
61
00
0b
03
00
6e
00
01
2. (1 point) Use Ethereal to capture IGMP packets that the host rigel.cse.sc.edu uses
to join and leave the multicast group 239.1.2.3. Save the captured packets in a file
named “IGMPxxxx”, where xxxx stands for the last 4 digits of your SSN, and submit the
file along with your homework. (Hint: The IGMP implemented in rigel.cse.sc.edu is
Version 2, so a Leave Group packet will be sent out when rigel leaves a multicast
group.)
3. (2 points) Use Ethereal to capture DNS query packets for the domain name
www.uz.ac.zw. Save the captured packets in a file named “DNSxxxx”, where xxxx
stands for the last 4 digits of your SSN, and submit the file along with your homework.
What is the canonical name for www.uz.ac.zw?
You need to submit your neatly typed answers for the problems via the Dropbox named
homework02. In order to get the points, you need to explain your answer when you are
asked to. This homework is due on Mar. 4 at 4pm.