MAC Address Flapping between ports

Answered Question
Mar 13th, 2007
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I have an ESX server with two NIC's connected to two seperate 2960 switches (for reducnecy presumably) The two 2960 have a trunk to the core switch 4507. In the syslog I see the following message:Host 00:50:56:47:9B:88 in vlan 104 is flapping between port Gi7/4 and port Gi7/6

How can i stop this 'flapping' occuring?


Thanks

Stewart

Correct Answer by dgahm about 10 years 4 months ago

Stewart,

The server NIC teaming needs to be set for fault tolerant, meaning only one active with the other standby. If they are set for load balancing the NICs need to be connected to the same switch on an etherchannel.


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Dave

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Correct Answer
dgahm Tue, 03/13/2007 - 08:02
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Stewart,

The server NIC teaming needs to be set for fault tolerant, meaning only one active with the other standby. If they are set for load balancing the NICs need to be connected to the same switch on an etherchannel.


Please rate helpful posts.


Dave

b.petronio Tue, 03/13/2007 - 08:12
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As the previous poster sayed, they have configured the NIC in Load Balance feature, and in this case u need to configure a Etherchannel as well in the switching side, so u need to configure the both ports in the same switch.


The Server is balancing information between the two nic's, and because of that the same MAC Address it is seen by the 4507, in different ports.


Best Regards,

Petr?nio

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