Capture

_$: tcpdump -i eth0 src 192.168.1.10        # Traffic from 192.168.1.10
_$: tcpdump -i eth0 dst 192.168.1.10        # Traffic to 192.168.1.10
_$: tcpdump -i eth0 host 192.168.1.10       # Traffic from/to 192.168.1.10
_$: tcpdump -i eth0 port 53                 # Traffic in the port 53
_$: tcpdump -i eth0 udp and src port 53     # UDP traffic UDP in the port 53 (DNS queries)
_$: tcpdump -i eth0 icmp                    # ICMP traffic

Write to a file

_$: tcpdump [...] -w /tmp/file.pcap         # No olvidar los filtros de captura

Read from a file

_$: tcpdump -nr /tmp/file.pcap