By default, the packet sniffing service captures packets and Ethernet frames from all the router’s interfaces. You can use the capture interface command to limit packet sniffing to a specific interface.

For example, the following command limits packet sniffing to the FastEthernet Interface:

Gxxx-001(super)# capture interface fastethernet 10/3
Done!
Gxxx-001(super)#

The following command enables packet sniffing on all available interfaces:

Gxxx-001(super)# capture interface any
Done!
Gxxx-001(super)#