Networking Wireshark Lab Homework Pearson Education Inc Upper Saddle River Nj

Unlock access to all the studying documents.

View Full Document

Wireshark Lab: Ethernet &

ARP SOLUTION

Supplement to Computer Networking: A Top-Down

Approach, 6th ed., J.F. Kurose and K.W. Ross

1. What is the 48-bit Ethernet address of your computer? The Ethernet address of my

2. What is the 48-bit destination address in the Ethernet frame? Is this the Ethernet

address of gaia.cs.umass.edu? (Hint: the answer is no). What device has this as its

Ethernet address? [Note: this is an important question, and one that students

3. Give the hexadecimal value for the two-byte Frame type field. What upper layer

protocol does this correspond to? The hex value for the Frame type field is

4. How many bytes from the very start of the Ethernet frame does the ASCII “G” in

“GET” appear in the Ethernet frame? The ASCII “G” appears 52 bytes from the

Here is a screenshot of the Ethernet frame containing the HTTP OK response:

5. What is the value of the Ethernet source address? Is this the address of your

computer, or of gaia.cs.umass.edu (Hint: the answer is no). What device has this

as its Ethernet address? The source address 00:0c:41:45:90:a8 is neither the

6. What is the destination address in the Ethernet frame? Is this the Ethernet address

of your computer? The destination address 00:09:5b:61:8e:6d is the address of

7. Give the hexadecimal value for the two-byte Frame type field. What do the bit(s)

whose value is 1 mean within the flag field? The hex value for the Frame type

8. How many bytes from the very start of the Ethernet frame does the ASCII “O” in

“OK” (i.e., the HTTP response code) appear in the Ethernet frame? The ASCII

9. Write down the contents of your computer’s ARP cache. What is the meaning of

each column value? The Internet Address column contains the IP address, the

10. What are the hexadecimal values for the source and destination addresses in the

Ethernet frame containing the ARP request message? The hex value for the source

11. Give the hexadecimal value for the two-byte Ethernet Frame type field. What do

the bit(s) whose value is 1 mean within the flag field? The hex value for the

12. Download the ARP specification from ftp://ftp.rfc-editor.org/innotes/std/std37.txt.

A readable, detailed discussion of ARP is also at

http://www.erg.abdn.ac.uk/users/gorry/course/inet-pages/arp.html.

a) How many bytes from the very beginning of the Ethernet frame does the

b) What is the value of the opcode field within the ARP-payload part of the

c) Does the ARP message contain the IP address of the sender? Yes, the ARP

message containing the IP address 192.168.1.105 for the sender.

d) Where in the ARP request does the “question” appear – the Ethernet

address of the machine whose corresponding IP address is being queried?

Here is the screenshot for the ARP reply message:

13. Now find the ARP reply that was sent in response to the ARP request.

a) How many bytes from the very beginning of the Ethernet frame does the

b) What is the value of the opcode field within the ARP-payload part of the

Ethernet frame in which an ARP response is made? The hex value for

opcode field withing the ARP-payload of the request is 0x0002, for reply.

c) Where in the ARP message does the “answer” to the earlier ARP request

appear – the IP address of the machine having the Ethernet address whose

14. What are the hexadecimal values for the source and destination addresses in the

Ethernet frame containing the ARP reply message? The hex value for the source

15. Open the ethernet-ethereal-trace-1 trace file in

http://gaia.cs.umass.edu/wireshark-labs/wireshark-traces.zip. The first and second

ARP packets in this trace correspond to an ARP request sent by the computer

running Wireshark, and the ARP reply sent to the computer running Wireshark by

the computer with the ARP-requested Ethernet address. But there is yet another

computer on this network, as indicated by packet 6 – another ARP request. Why