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Webcast-Catalyst9k
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Mac flapping on stack

Hello Community,

could you please provide some insight on the following issue?

We have two switches WS-C2960S-24TS-L running in stack with running IOS c2960s-universalk9-mz.122-55.SE3.

We have connected two checkpoint devices on Gi1/0/24 and Gi2/0/24 with a simple configuration:

interface range GigabitEthernet1/0/24, gi2/0/24

switchport access vlan x

switchport mode access

spanning-tree portfast

On the devices log we get the following message:

%SW_MATM-4-MACFLAP_NOTIF: Host 0000.0000.fe21 in vlan x is flapping between port Gi2/0/24 and port Gi1/0/24

The mac-address 0000.0000.fe21 is not found on any checkpoint interface. "Show mac-address int gi1/0/24 or gi2/0/24" does not show the correct mac-address of the checkpoint interface connected to the port, but instead shows 0000.0000.fe21.

Is there a bug in the IOS, something wrong with the switch config or does it have something to do with the checkpoint config?

Thank you in advance,

Katerina

2 REPLIES

Mac flapping on stack

Hi Katerina,

It could be problem with ports configuration.
I recommend you change it to Auto negotiation in Check Point and switch side.


Please rate all the helpfull posts.
Regards,
Naidu.

New Member

Mac flapping on stack

Naidu,

thank you for your reply. We just got an answer from the guys that were supposed to configure the checkpint. At first they said that this was an IOS bug, which I couldn't find anywhere (that is why I required the community's assistance) but after some searching of their own, they verified that the message is due to not fully configuring the checkpoint.

Thank you for your support.

Katerina

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