To refresh dynamically created entries from the Address Resolution Protocol (ARP) cache, use the clear arp-cache command in privileged EXEC mode.
This command updates the dynamically learned IP address and MAC address mapping information in the ARP table to ensure the validity of those entries. If the refresh operation encounters any stale entries (dynamic ARP entries that have expired but have not yet been aged out by an internal, timer-driven process), those entries are aged out of the ARP table immediately as opposed to at the next refresh interval.
You can enter the ip sticky-arp (interface configuration) command to disable sticky ARP on a specific interface.
ARP entries that are learned on Layer 3 interfaces are sticky ARP entries. We recommend that you display and verify ARP entries on the Layer 3 interface using the show arp command.
For security reasons, sticky ARP entries on the Layer 3 interface do not age out. Connecting new equipment with the same IP address generates a message and the ARP entry is not created.
Because the ARP entries on the Layer 3 interface do not age out, you must manually remove ARP entries on the Layer 3 interface if a MAC address changes.
Unlike static entries, sticky-ARP entries are not stored and restored when you enter the reboot and restart commands.
