WarningSyslog message

Unanswered Question
Jun 25th, 2008

Hi everyone,

I have received the following message, and would like to know what it means and what can be done to stop it. Host 0019.7eaf.ddc8 in vlan 198 is flapping between port Fa2/0/21 and port Fa2/0/30.

Thanks for your help


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Overall Rating: 2.3 (3 ratings)
massimiliano.se... Wed, 06/25/2008 - 05:30


This message means that probably you have a loop on your network.

Check it.

I hope this helps.

Best regards.


glen.grant Wed, 06/25/2008 - 07:02

Probably someone plugged a cable in between those two ports somehow . It should block itself off via spanning tree . see if the switch sees itself via cdp on those ports . Also see if spanning tree is blocking either of those ports via show spanning tree blockedports command.

hipohoneywell Wed, 06/25/2008 - 07:57

I tried the command, but the blocking ports are correct. I have 2 access points connected on those ports, and the mac address belongs to a wireless device.

Any idea?


massimiliano.se... Wed, 06/25/2008 - 09:16


Probably the wireless device associates alternatively between two access point resulting in a flapping of its mac address on the port of switch.

Or the two access point form a wireless bridhe between them....in this way you have a loop.

I hope this helps.

Best regards.


hipohoneywell Wed, 06/25/2008 - 09:53

5770: Jun 25 11:01:20.624: %SW_MATM-4-MACFLAP_NOTIF: Host 0019.7d37.fd25 in vlan 901 is flapping between port Fa2/0/12 and port Fa2/0/9

Knock yourself out.



Last message is from another switch.


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