Wireshark Lab: UDP
SOLUTION
Supplement to Computer Networking: A Top-Down
Approach, 6th ed., J.F. Kurose and K.W. Ross
1 0.000000 192.168.1.102 192.168.1.104 SNMP
92 get–request 1.3.6.1.4.1.11.2.3.9.4.2.1.2.2.2.1.0
Dst: 192.168.1.104 (192.168.1.104)
User Datagram Protocol, Src Port: 4334 (4334), Dst Port: snmp (161)
1. Select one UDP packet from your trace. From this packet, determine how many
fields there are in the UDP header. (You shouldn’t look in the textbook! Answer
2. By consulting the displayed information in Wireshark’s packet content field for
this packet, determine the length (in bytes) of each of the UDP header fields.
3. The value in the Length field is the length of what? (You can consult the text for
4. What is the maximum number of bytes that can be included in a UDP payload?
(Hint: the answer to this question can be determined by your answer to 2. above).
5. What is the largest possible source port number? (Hint: see the hint in 4.) Answer:
6. What is the protocol number for UDP? Give your answer in both hexadecimal and
7. Examine a pair of UDP packets in which the first packet is sent by your host and
the second packet is a reply to the first packet. Describe the relationship between
the port numbers in the two packets. Answer: Let’s look at packets 1 and 2 in the
trace. These packets carry SNMP application-level messages encapsulated inside
of UDP. (Got that? If not, re-read section 1.5 and Figure 1.24 in the text, in
