Getting started with TCPDump

To start off, let's look at the usage specification for TCPDump:

tcpdump [ -AbdDefhHIJKlLnNOpqRStuUvxX ]

[ -B buffer_size ] [ -c count ] [ -C file_size ]

[ -G rotate_seconds ] [ -F file ]

[ -i interface ] [ -j tstamp_type ] [ -m module ] [ -M secret ]

[ -Q in|out|inout ] [ -r file ]

[ -V file ] [ -s snaplen ] [ -T type ] [ -w file ] [ -W filecount ]

[ -E spi@ipaddr algo:secret,... ] [ -y datalinktype ]

[ -z postrotate-command ] [ -Z user ] [ expression ]