Display packtes from <host> on interface eth0, no name resolution:
tcpdump -i eth0 -s 0 -nnn host <HOST>
Save packets to tracefile <filename> on interface eth0 with the exclusion of SSH traffic:
tcpdump -i eth0 -s 0 -w <filename> port not 22
Save icmp packets to tracefile <filename> on interface eth0:
tcpdump -i eth0 -s 0 -w <filename> icmp
Packets from host A.B.C.D on port 1234
tcpdump -i eth0 -s 0 host A.B.C.D && port 1234
Packets on port 1234 for 10 minutes (dump tracefile <filename> once after 600 seconds):
tcpdump -i eth0 -s 0 -G 600 -W 1 -s 0 -w <filename> port 1234
To stop:
<Enter>