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Webcast-Catalyst9k
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ETHCNTR-3-LOOP_BACK_DETECTED

I have this error on one of the switches and the port is being disable (GBIC Port) because of that. Nothing but computers and printers are connected to it. I have disable the keepalive on the port so it won't get disable. But still why is getting the error. Any Ideas?

Thanks.

1 REPLY
Bronze

Re: ETHCNTR-3-LOOP_BACK_DETECTED

The problem occurs because the keepalive packet is looped back to the port that sent the keepalive. There is a loop in the network. Although disabling the keepalive will prevent the interface from being errdisabled, it will not remove the loop.

Did you disable Portfast feature on those ports?. Because, when removing portfast on uplink ports this could be the reason why the messages appear. In the event the portfast configs were removed in the ports, it will automatically go to listening, learning, etc.. STP process and topology changes notifications will happen

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