Yesterday we had a situation with two switch stacks going down. The logs showed the following message ETHCNTR-3-LOOP_BACK_DETECTED: Keepalive packet loop-back detected. To resolve the issue we had to shut then no shut the ports which had error disabled. I understand the keepalive packet is looped back to the port that sent the keepalive. What would be the best method to determine the device that has caused this loop? We have rapid-pvst enabled on all our switches.
After looking at the logs of some of the other switches which we use to connect to our other site I've noticed the following messages.
%C4K_EBM-4-HOSTFLAPPING: Host 08:00:0B:EE:28:69 in vlan 12
Could these errors be related?