arpspoof [-i interface] [-t target] host
arpspoof redirects packets from a target host (or all hosts) on the LAN intended for another host on the LAN by forging ARP replies. This is an extremely effective way of sniffing traffic on a switch.
Kernel IP forwarding (or a userland program which accomplishes the same, e.g. fragrouter(8)) must be turned on ahead of time.
Specify the host you wish to intercept packets for (usually the local gateway).
Dug Song <email@example.com>