Tcpdump can sniff and capture packets across the network.

Usage

tcpdump <parameter>

$ command

Important Flags

-i: Interface to sniff
-X: Hex output

Important Modules

port: Specified port address
icmp: Traffic on specific protocols
host: Specifies hostname IP
src: Captures from source IP
dst: Captures packets to destination IP
net: Packets on specified network/subnet