sudo tcpdump -i en0 -vvv -n -s 0 -w ~/Desktop/DumpFile.dmpNote: Both "en0" and "-s 0" include a zero, not the letter O.For AirPort, type:
sudo tcpdump -i en1 -vvv -n -s 0 -w ~/Desktop/DumpFile.dmp
As you are using the 'sudo' command you will need to enter your password. Once you've done that though all packet information will be saved to the 'Dumpfile.dmp' on your desktop. Once you've finished all the logging press Control-C from the Terminal.