Monitoring Interface Status
Commands entered at the privileged EXEC prompt display information about the interface, including the versions of the software and the hardware, the configuration, and statistics about the interfaces. Table 9-3 lists some of these interface monitoring commands. (You can display the full list of show commands by using the show ? command at the privileged EXEC prompt.) These commands are fully described in the Cisco IOS Interface Command Reference for Release 12.1.

Table 9-3 Show Commands for Interfaces

Command

Purpose

show interfaces [interface-id]

Display the status and configuration of all interfaces or a specific interface.

show interfaces interface-id status [err-disabled]

Display interface status or a list of interfaces in an error-disabled state.

show interfaces [interface-id] switchport

Display administrative and operational status of switching ports.

show interfaces [interface-id] description

Display the description configured on an interface or all interfaces and the interface status.

show ip interface [interface-id]

Display the usability status of all interfaces configured for IP routing or the specified interface.

show running-config interface [interface-id]

Display the running configuration in RAM for the interface.

show version

Display the hardware configuration, software version, the names and sources of configuration files, and the boot images.

show controllers ethernet-controller interface-id phy

Verify the operational state of the Auto-MDIX feature on the interface.

Clearing and Resetting Interfaces and Counters
Table 9-4 lists the privileged EXEC mode clear commands that you can use to clear counters and reset interfaces.

Table 9-4 Clear Commands for Interfaces

Command

Purpose

clear counters [interface-id]

Clear interface counters.

clear interface interface-id

Reset the hardware logic on an interface.

clear line [number console 0 vty number]

Reset the hardware logic on an asynchronous serial line.

To clear the interface counters shown by the show interfaces privileged EXEC command, use the clear counters privileged EXEC command. The clear counters command clears all current interface counters from the interface unless optional arguments are specified to clear only a specific interface type from a specific interface number.