Wireshark_TCP_Solution_July_22_2007.pdf

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Wireshark Lab 3 – TCP

The following reference answers are based on the trace files provided with the text book,

which can be downloaded from the textbook website.

TCP Basics

Solution: Client computer (source)

IP address: 192.168.1.102

TCP port number: 1161

Destination computer: gaia.cs.umass.edu

IP address: 128.119.245.12

TCP port number: 80

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trace.

The SYN flag is set to 1 and it indicates that this segment is a SYN segment.

3. (2 points) What is the sequence number of the SYNACK segment sent by

gaia.cs.umass.edu to the client computer in reply to the SYN? What is the value

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The value of the ACKnowledgement field in the SYNACK segment is 1. The value of the

ACKnowledgement field in the SYNACK segment is determined by gaia.cs.umass.edu

4. (1 point) What is the sequence number of the TCP segment containing the HTTP

POST command? Note that in order to find the POST command, you’ll need to

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5. (2 points) Consider the TCP segment containing the HTTP POST as the first

segment in the TCP connection. What are the sequence numbers of the first six

segments in the TCP connection (including the segment containing the HTTP

of the six segments? What is the EstimatedRTT value (see page 237 in text)

gaia.cs.umass.edu server. Then select: Statistics->TCP Stream Graph-

>Round Trip Time Graph.

Solution: The HTTP POST segment is considered as the first segment. Segments 1 – 6

are No. 4, 5, 7, 8, 10, and 11 in this trace respectively. The ACKs of segments 1 – 6 are