TCPDump
First of all, I realized in order to use the TCPDump tool, I have to be in super user mode, so I typed SU at the command line and then started the TCPDump. I noticed a lot of ARP traffic.
Then I pinged my neighbor (129.7.236.255) using another command window and when I looked back at my TCPDump window, I could see my IP address (129.7.236.75) and the traffic that was going between his and my computer. See below:
