Unanswered Question
May 13th, 2009

Dear all

Running 12.2(31)SGA4 on 4510R.

ARP entries do not flush even when timout is configured (300s). no ip sticky-arp is also configured since i am using PVLANs.

manually cleared entries do not re-appear.

I have looked up known bugs but cannot see any.

Any suggestions or thoughts would be helpful !



I have this problem too.
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mchin345 Tue, 05/19/2009 - 15:07

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.


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