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Author Topic: Strange MAC learning issue  (Read 3486 times)

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Offline adagre

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Strange MAC learning issue
« on: December 02, 2014, 03:27:56 PM »
I have been noticing a strange issue across our network over the last year, to which we have not found a solution.

With MAC security autloearn max-mac 1, sometimes on certain 5520 stacks, the Auth Config table loses mac addresses, when the device is swapped out a new mac is not learnt and causes security to trip.

This only affects the downstream switches in the stack, never the base unit.

Also this effects the same stacks over and over, we will blow away the security settings and start fresh, then mac addresses will disappear again over time. The devices will continue to work fine until they are swapped out etc.


Any ideas?



Offline Michael McNamara

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Re: Strange MAC learning issue
« Reply #1 on: December 18, 2014, 05:38:06 PM »
What version of software?

When you say "swapped out" you mean you are connecting a different device to the switch port than the original device.

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Offline adagre

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Re: Strange MAC learning issue
« Reply #2 on: February 25, 2015, 01:19:10 PM »
Bringing this back from the dead, we are still experiencing this issue on a somewhat regular basis.

Yes Michael it is when the device is changed, usually due to a lifecycle process or similar.

It works in many areas without a problem, it seems to be certain stacks. All 5510/20's are at 6.2 firmware.

The image attached shows the AuthConfig table when this is happening, eventually all mac addresses other than those on the base unit will disappear from this list. I know once this is happened if the device is swapped it will trip security. We are only tying to prevent multiple macs and are not concerned with specified MAC security.

As a temporary solution we have been removing security, rebooting the stack and reapplying, eventually the problem will return.


Offline TankII

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Re: Strange MAC learning issue
« Reply #3 on: March 11, 2015, 10:31:13 AM »
5500 series specific item:
Make sure FilterUnregisteredFrames is NOT enabled on the ports.
Similar problem cropped up with an updated Avaya 1692 firmware.  Disabling that addressed the problem.

TankII

Offline adagre

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Re: Strange MAC learning issue
« Reply #4 on: March 11, 2015, 03:45:06 PM »
Thanks TankII, I will give this a shot. We do have filter unregistered frames enabled on all edge ports.

Offline adagre

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Re: Strange MAC learning issue
« Reply #5 on: November 16, 2015, 10:48:33 AM »
TankII's suggestion has resolved this issue.

Offline TankII

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Re: Strange MAC learning issue
« Reply #6 on: November 17, 2015, 06:37:36 AM »
Glad it worked!
TankII