UDP Lab Exercises


The following exercises are to familiarize you with the UDP 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!)

  1. Use ping to ping another node by name not IP addresses (why?), a couple of times (i.e. use the -c flag) and examine (using the sniffer of your choice) resulting packets. Specifically examine the UDP packets.

  2. Be able to identify all relevant pieces (in the hex output) of the UDP and encapsulating packets.

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