Tcpdump

tcpdump is a command that allows you to monitor your network traffic.

Examples

dhcp

You can watch out for dhcp communication on your network using:

tcpdump -i eth1 port 67 and port 68

SNMP

You can display incoming snmp traps using:

tcpdump -A port 162 -l | hexdump -C

See also

• nmap
• netstat
• netcat
• tcpdump man page