-s Snarf snaplen bytes of data from each packet rather than the default of 65535 bytes. Packets
truncated because of a limited snapshot are indicated in the output with ``[|proto]'', where proto
is the name of the protocol level at which the truncation has occurred. Note that taking larger
snapshots both increases the amount of time it takes to process packets and, effectively,
decreases the amount of packet buffering. This may cause packets to be lost. You should limit
snaplen to the smallest number that will capture the protocol information you're interested in.
Setting snaplen to 0 sets it to the default of 65535, for backwards compatibility with recent
older versions of tcpdump.