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Wireshark Lab: ICMP
SOLUTION
Supplement to Computer Networking: A Top-Down
Approach, 6th ed., J.F. Kurose and K.W. Ross
Figure 1: Screenshot after the PING request
1. What is the IP address of your host? What is the IP address of the destination
2. Why is it that an ICMP packet does not have source and destination port
numbers because it was designed to communicate network-layer information
between hosts and routers, not between application layer processes. Each ICMP
packet has a "Type" and a "Code". The Type/Code combination identifies the
specific message being received. Since the network software itself interprets all
ICMP messages, no port numbers are needed to direct the ICMP message to an
application layer process.
Figure 2: ICMP Echo Request message
3. Examine one of the ping request packets sent by your host. What are the ICMP
type and code numbers? What other fields does this ICMP packet have? How
4. Examine the corresponding ping reply packet. What are the ICMP type and code
numbers? What other fields does this ICMP packet have? How many bytes are the
6. If ICMP sent UDP packets instead (as in Unix/Linux), would the IP protocol
8. Examine the ICMP error packet in your screenshot. It has more fields than the
9. Examine the last three ICMP packets received by the source host. How are these
packets different from the ICMP error packets? Why are they different?
Figure 7: Command prompt for traceroute
10. Within the tracert measurements, is there a link whose delay is significantly
longer than others? Refer to the screenshot in Figure 4, is there a link whose
delay is significantly longer than others? On the basis of the router names, can
