Handy Cisco Commands

Network Sniffing

When you have a Cisco Catalyst switch at your disposal you are able to mirror ports in order to monitor them.

$ en
# config t
# interface fa0/x
# port monitor fa0/a
# port monitor fa0/b
# port monitor fa0/c
# ^z

(it's in short hand)

fa0/x is the port that you plug in the monitoring device or PC, fa0/a, fa0/b, fa0/c are the ports that you wish to monitor.