Tcpdump

Display Available Interfaces

tcpdump -D

Capture Packets from Specific Interface

tcpdump -i eth0

Print Captured Packets in ASCII

tcpdump -A -i eth0

Display Captured Packets in HEX and ASCII

tcpdump -XX -i eth0

Capture only TCP Packets.

tcpdump -i eth0 tcp

Capture only UPD Packets.

tcpdump -i eth0 udp

Capture Packet from Specific Port

tcpdump -i eth0 port <port>

Capture Packets from source IP

tcpdump -i eth0 src <ip>

Capture Packets from destination IP

tcpdump -i eth0 dst <ip>