I have to sniff the traffic from the outside interface of a remote-site router, 2801. The router has only 2 Fa ports, and they are currently occupied: one for connecting to the service provide and the other, connecting to the office LAN.
In the documentation, I've read that SPAN can be configured on 2800 only if ethernet switch module is installed.
How could I sniff the traffic on the fa0/1 (to service provider) interface with Ethereal? Is it possible at all?