Hello,
I have a MAC address that is flapping intermittently on a 2960X switch and I am unable to locate the other interface since it is not local to the device and we have over one hundred switches in our environment. I need help finding a method to track down the culprit. Here is my situation.
Every so often (though it's becoming more frequent) I see the following message appear 4-5 times within a 1-3 hour period on one of my access switches.
%SW_MATM-4-MACFLAP_NOTIF: Host xxxx.xxxx.67e3 in vlan 2 is flapping between port Po3 and port Gi1/0/10
Po3 is our uplink port-channel to the core 6807 switch. The end device is a tangent PC with a single ethernet connection. The PC has two ethernet ports, but the problem has followed after we switched between them. It is capable of wireless, but not active. I have gone through each switch (which took a while) and used the following command to see if I could find similar messages and trace down where the other duplicate MAC was showing up.
show logging | inc xxxx.xxxx.67e3
So far I have not been able to track down where the MAC conflict is coming from. The core switch did not have any entries for any MAC flaps either. Is there a command I can use to help pin down the other end of the MAC conflict so I can resolve? I am beginning to think there is an un-managed switch somewhere in my environment, but given it is intermittent and it is layer 2 the behavior does not logically fit.
