Sometimes it is hard to catch some traffic on remote machine or test local applications on real environment  ... or to spy some obscure traffic.
This is the moment etherpuppet makes your live easier :-)

#remote machine
etherpuppet -i eth1 -s 999 -C

# from local workstation
etherpuppet -m -c xxx.xxx.xxx.xxx:999 (fill in xxx with ip adress of the router)
ifconfig puppet0 up
# now you can use wireshark or other handy tools ... local :-)