We can get basic network informations (to start an analysis) with the following command (as root):

tcpdump -nntttte -i <interface> -A -s0

The option:

  • -nn: unactivates the name and port resolution
  • -tttt: displays the date and the hour in a readable format
  • -e: adds the MAC address
  • -i: selects the network interface
  • -A: displays the data in ASCII format
  • -s0: forces the display of all the contents (otherwise there could be some truncatures)