asked on 3/19/2007

Err-disabled stat on cisco switch port

I am intermittently having ports shut down on switches throughout my company. The switches I have are Cisco 3560 catalyst. When I check the port it is in an err-disable state. I can bring the port up by doing the shutdown no shutdown command on the interface. When I check the status on the port to see why it went down the reason listed is bpduguard. Bpduguard is enabled on the port. But my understanding was bpduguard detected bpdu packet. I though bpdu packets only came from devices like switches. The devices that are connected to the ports that go into the err-disable state are computers (Dell 9200). Why would the switch think that the computers are sending out bpdu packets.

Any insight would be most appreciated.

Switches / Hubs

Last Comment

SHAX

1/2/2008

Don Johnston

3/19/2007

SOMETHING caused a BPDU to come in that port. It could be that a user connected an unauthorized switch or maybe a cable got connected so that a loop was created.

The only time I've seen a computer generate a BPDU is if has multiple NIC's and it is configured to bridge the traffic between the NICs.

It sounds like some investigating is in order. :-o

SHAX

11/9/2007

ASKER

*****Updated info for original post.***** The NIC that we are seeing the BPDU's from are the Intel 82566 DC Integrated NIC in the Dimension 9200 desktop models. As to the comment by donjohnson, the users are not plugging in unauthorized switches, nor have any cabling changes been made. Thanks for the suggestion, but that isn't the case in this situation. Any other comments and suggestions will be welcome.

Thanks

SOLUTION

Don Johnston

11/9/2007