RE: Difference between bpduguard & bpdufilter

From: Gustavo Novais (gustavo.novais@novabase.pt)
Date: Fri Oct 14 2005 - 06:39:35 GMT-3


Hi

I didn't understand why you say that spanning-tree bpdufilter is
dangerous on the interface level, because it disables STP on the port,
but globally it is safe? I thought it would be as dangerous enabling it
at global level (disable STP on ALL portfast ports) as it would be
interface level (if not more!).

At least the DocCD does not state anything that one command is safe and
the other is not.

Could you elaborate on that?

Thanks

Gustavo

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Bob Sinclair
Sent: sexta-feira, 14 de Outubro de 2005 3:10
To: Matthew Seppeler; ccielab@groupstudy.com
Subject: Re: Difference between bpduguard & bpdufilter

Matthew,

Here are some of my notes:

BPDU Guard:

error-disables port if a portfast port receives a bpdu

enable on all portfast ports: spanning-tree portfast bpduguard default

enable per port: spanning-tree bpduguard [enable disable]

BPDU Filtering:

When enabled globally prevents portfast ports from sending bpdus. If
bpdu is received, port becomes non-portfast and filtering is disabled

spanning-tree portfast bpdufilter default

On interface: DISABLES STP on the port: very dangerous!

spanning-tree bpdufilter enable

Global is recommended, per interface is dangerous.

HTH,

Bob Sinclair
CCIE #10427, CCSI 30427, CISSP
www.netmasterclass.net

  ----- Original Message -----
  From: Matthew Seppeler
  To: ccielab@groupstudy.com
  Sent: Thursday, October 13, 2005 8:09 PM
  Subject: Difference between bpduguard & bpdufilter

  Can someone explain the differences between bpduguard & bpdufilter and
  under which circumstances they would it best be used. The Doc CD does
  not make a clear distinction between the two.

  Matt Seppeler

 



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