ICMP Lab Exercises

The following exercises are to familiarize you with the ICMP protocol and its functionality as discussed in class. The following commands will be necessary in completing the following steps: ping, traceroute, ifconfig, ethereal and/or tcpdump. If any of these commands are unfamiliar, refer to the man page for that command.

Note: the ethereal sniffer sits on top of tcpdump and provides a nice window based UI for you to examine network packets. Since it sits on top of tcpdump, several of the command inputs are the same, such as the packet filters. This will require you to be familiar with tcpdump (or at least have access to the tcpdump man pages. You have been warned!)

Use ping to ping another node (it can be a neighbor) a couple of times (i.e. use the -c flag) and examine (using the sniffer of your choice) resulting ICMP packets. Notice what changes in each packet capture. You might use the filter
```
	ip host your_ip_address
```

Use traceroute to connect to a remote host (not too far away), sniff and examine the ICMP packets captured, as follows
```
	traceroute -q1 -I host		(search for -q on man page)
```

Complete the ICMP review exercise handed out in class.

NOTE: If you choose to print, ALWAYS USE PRINT PACKET, NOT PRINT!