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Host Flapping messages in the syslog

spfeffer
Level 1
Level 1

Can anyone tell me why this would all of a sudden start happening? I'm confused. No configuration changes have occurred. This kind of stuff just starts coming up on my switches randomly from time to time.

Sonny

1 Reply 1

Edison Ortiz
Hall of Fame
Hall of Fame

Sonny,

You have multiple devices attached to this switch announcing the same MAC Address. Usually, you see these messages when you configure etherchanneling in one end and forget to configure the same in the other end. You also see these messages when you configure load balancing on a server.

From your log, it seems G1/1 is the common denominator. Can you tell us what is this device? P

Perhaps the hosts on blade 2 are also connected to this device hence creating a loop ?

To avoid loops in a switched network, you need to make sure not to have spanning-tree portfast enable on ports connected to another switch.

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