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tcpdump Cheat Sheet

Filter Examples

Check out tcpdump - Tutorial for many usage examples!

    # Filter port
    tcpdump port 80
    tcpdump src port 1025 
    tcpdump dst port 389
    tcpdump portrange 21-23

    # Filter source or destination IP
    tcpdump src 10.0.0.1
    tcpdump dest 10.0.0.2

    # Filter  everything on network 
    tcpdump net 1.2.3.0/24

    # Logically operators
    tcpdump src port 1025 and tcp 

    # Provide full hex dump of captured HTTP packages
    tcpdump -s0 -x port 80

    # Filter TCP flags (e.g. RST)
    tcpdump 'tcp[13] & 4!=0'

Capture and Replay

tcpdump <filter> -w <output file>
tcpdump <filter> -r <output file>

Verbose Trace

Be verbose and print 1500 bytes package hex dumps:

tcpdump -i eth0 -nN -vvv -xX -s 1500 port <some port>

Same but with ASCII package dump

tcpdump -i eth0 -nN -vvv -A -s 1500 port <some port>

Non-promiscous mode

tcpdump -e ...