Link flapping with Mac address of a disconnected server

[tstaba25]

Hello,

 I have a weird situation where i get in logs that mac address is flapping:

264094: *Nov  7 15:10:32 GMT: %SW_MATM-4-MACFLAP_NOTIF: Host 4c52.6211.ac36 in vlan 19 is flapping between port Twe1/0/24 and port Twe2/0/24

264095: *Nov  7 15:10:47 GMT: %SW_MATM-4-MACFLAP_NOTIF: Host 4c52.6211.ac36 in vlan 19 is flapping between port Twe2/0/24 and port Twe1/0/24

264096: *Nov  7 15:11:02 GMT: %SW_MATM-4-MACFLAP_NOTIF: Host 4c52.6211.ac36 in vlan 19 is flapping between port Twe2/0/24 and port Twe1/0/24

264097: *Nov  7 15:11:17 GMT: %SW_MATM-4-MACFLAP_NOTIF: Host 4c52.6211.ac36 in vlan 19 is flapping between port Twe2/0/24 and port Twe1/0/24

The thing is that that MAC address belongs to an interface on ESXi host that is not connected , no cable is in there.  It only happens on this particular VLAN.

What are the poissible solutions for this? is it really an error or perhaps flase positive?

Kind regards,

Tomislav

[DanielP211]

Hello,

The VM is being migrated between hosts. So this is a false positive and is seen a lot in the DC. So no need for any intervention. 

BR

[tstaba25]

Hello,

First of all, thanks for quick response.

Is it possible to see that mac address during migration if that NIC on ESX host is not conneceted, and it's not teaming with the others?

This happens a lot , VMs are not migrating that often.

BR

[MHM Cisco World]

no mac address-table notification mac-move

This will disable these messages.

For mac see it I think you can see it when migration.

[tstaba25]

OK, 

I applied this command and no errors of this kind are now logged. 

But does this command have some other consequenses or minuses when switch is running?

I mean, If there will be any layer 2 loop or something, will it report warning or error?

BR

[MHM Cisco World]

Unfortunately yes 

It will disappear all mac move notifications.

But it way to make your log not full with these log message.

[tstaba25]

I have checked logs on Vsphere, and there is no migration done in these intervals, this happens every few minutes.

BR

[MHM Cisco World]

do VM using any team Port-Channel ??