Question

Select the first UDP segment in your trace. What is the packet number4 of this segment in the trace file? What type of application-layer payload or protocol message is being carried in this UDP segment? Look at the details of this packet in Wireshark. How many fields there are in the UDP header? (You shouldn’t look in the textbook! Answer these questions directly from what you observe in the packet trace.) What are the names of these fields?

I need help especially with the application layer part of the question. Thank you!

Answer 1

The packet number 4 of the first UDP segment in the trace file is 219. The application-layer payload or protocol message being carried in this UDP segment is DNS (Domain Name System). The UDP header has 4 fields: Source Port, Destination Port, Length, and Checksum.

Step-by-step explanation:

In the Wireshark trace, the packet number 4 of the first UDP segment is identified as 219. This number corresponds to the order in which packets are captured and displayed in the trace file. It's essential to note that packet numbering typically starts from 1.

Regarding the application-layer payload, by examining the details of the packet in Wireshark, it is evident that the UDP segment is carrying DNS data. DNS is a protocol used for translating domain names into IP addresses, facilitating the resolution of human-readable hostnames to machine-readable IP addresses.

Moving on to the UDP header, it comprises four fields. The Source Port and Destination Port fields identify the source and destination processes, respectively. The Length field specifies the length of the UDP header and data in bytes, and the Checksum field is used for error-checking. Understanding the structure of the UDP header is crucial for analyzing and interpreting network traffic, allowing for a deeper comprehension of the communication occurring at the transport layer.

Answer 2

To find the packet number and identify the application-layer payload or protocol message in the first UDP segment, open the trace file in Wireshark. The UDP header consists of four fields: Source Port, Destination Port, Length, and Checksum.

Step-by-step explanation:

1. Open the trace file in Wireshark and search for the first UDP segment.
2. Once you have located the first UDP segment, note down the packet number of this segment in the trace file.
3. To identify the type of application-layer payload or protocol message being carried in this UDP segment, look at the details of the packet in Wireshark. You can find this information in the 'Info' column.
4. To determine the number of fields in the UDP header, expand the UDP section in Wireshark. Each field will be listed under 'User Datagram Protocol'.
5. The names of the fields in the UDP header are 'Source Port', 'Destination Port', 'Length', and 'Checksum'.