Mac address flapping issue

ruesch-eng · ‎04-10-2010

I am seeing mac address flapping on my 2960 switch. I entered a static mac address table entry, but that did not resolve the issue. The flapping still continues. And when I do a sh mac address-table command, I see that both a static entry and a dynamic entry exist for that address. I am running 12.2(35)SE5. How can I resolve this issue? Thanks.

Reza Sharifi · ‎04-10-2010

Hi,

There could be multiple things that can cause MAC flapping.

Take a look at this paper

http://www.cisco.com/en/US/partner/products/hw/switches/ps663/products_tech_note09186a00801434de.shtml#subtopic1k

HTH

Reza

Ganesh Hariharan · ‎04-11-2010

I am seeing mac address flapping on my 2960 switch. I entered a static
mac address table entry, but that did not resolve the issue. The
flapping still continues. And when I do a sh mac address-table command,
I see that both a static entry and a dynamic entry exist for that
address. I am running 12.2(35)SE5. How can I resolve this issue? Thanks.

Hi,

Mac-address flapping issue can come from host/server end,just check out the following things from server/host end that both the NIC are connected to different swiches and are in ACTIVE/PASSIVE fashion from server/host end.If both the nic are configured in Active/Active fashion then there will be mac flapping messages can come on switches.In order to troubleshoot just check the serve end configuration of NIC and try with Active/Passive mode from server end for load balancing.

Hope to Help !!

Ganesh.H

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