Clearing the access-list (ACL) counters is similar to resetting the trip odometer on your car and provides a clean slate for future reports. When making changes to the configuration, starting the ACL counters at zero grants more reliable data in relation to the current changes. A reset command must be performed within the CONFIG mode in order to restart that counter, or it won’t work.
To reset the ACL, type the command: “clear access-list counters” in CONFIG mode. Results for the ACL command are now cleared. Use the command: “clear int ethernet0” to clear counters in the interface. It might seem more natural to perform these commands within enable mode, but this only works in CONFIG.