BPDU Guard Errors On 3750

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Sep 19th, 2007
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We turned on BPDU and now ports will go disabled stating BPDU Guard disabled. I know there is no switch plugged into these ports, and there is no physical loop these ports have either pc's or server plugged into them. Why else could this be happening and how can we resolve this?

Thanks for any help.

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ankbhasi Wed, 09/19/2007 - 07:32
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Hi Am,

Can you confirm if you have portfast enabled on these interfaces? Also can you paste the output of "sh run int " on which you have configured bpdu guard?



amjbmr808 Wed, 09/19/2007 - 10:14
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Yes, portfast is enabled. Here is the results

78LINE#sh run int fastethernet 1/0/10

Building configuration...

Current configuration : 66 bytes


interface FastEthernet1/0/10

spanning-tree portfast trunk


paul.matthews Wed, 09/19/2007 - 08:09
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What is connected to the ports? BAsically BPDU guard putting the ports err-disable means the switch thinks it has seen a BPDU.

Some end systems (I am thinking mainly XP here, as other systems that can do it tend to be used more by knowledgable people) can be configured to bridge.

amjbmr808 Wed, 09/19/2007 - 09:52
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It is all XP pc's and HP Printers, and a few HP Proliant Server connected to the ports.

paul.matthews Wed, 09/19/2007 - 10:50
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Do printer ports come up with err-disable too?

In the cse of XP, go to a printer connected to a port that goes err-disable and check its network config for bridging.

paul.matthews Wed, 09/19/2007 - 12:28
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Sorry typo - I meant go to an XP PC, NOT a printer.

As an afterthought, do the printers have some form of built in switch to allow connection sharing?


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