From: CCIEin2006 (ciscocciein2006@gmail.com)
Date: Sun Feb 05 2006 - 12:00:03 GMT-3
I'm not sure what 0x8100 matches, but I did also read that post and tried
matching on lsap 0x42 but that did not help either.
Basically what I'm trying to do is to filter all non IP frames but still
allow BPDU's.
I noticed that if I allow the SSTP mac address 01-00-0c-cc-cc-cd then BPDU's
are allowed. I just wonder if there is a type code associated with SSTP that
I can match on instead of the mac address.
Any thoughts?
On 2/5/06, Henk de Tombe <henk.de.tombe@qi.nl> wrote:
>
> Hi,
>
> Are you sure that ethertype 0x8100 matches 802.1q bpdu's, or do they match
> something else?
>
> Take a look at the output of the trace below:
>
> Frame 861 (60 bytes on wire, 60 bytes captured)
> Time delta from previous packet: 4.276125000 seconds
> Time since reference or first frame: 4.276125000 seconds
> Frame Number: 861
> Packet Length: 60 bytes
> Capture Length: 60 bytes
> IEEE 802.3 Ethernet
> Destination: 01:80:c2:00:00:21 (01:80:c2:00:00:21)
> Source: 00:01:30:01:01:01 (ExtremeN_01:01:01)
> Length: 10
> Trailer: 00111411001E00010401001400000038...
> Logical-Link Control
> DSAP: Spanning Tree BPDU (0x42)
> IG Bit: Individual
> SSAP: Spanning Tree BPDU (0x42)
> CR Bit: Command
>
> You can take a look at this post where someone was trying to filter BPDU
> frames:
>
> http://www.groupstudy.com/archives/ccielab/200403/msg00329.html
>
>
> Regards,
> Henk
>
> -----Oorspronkelijk bericht-----
> Van: nobody@groupstudy.com [mailto:nobody@groupstudy.com] Namens
> CCIEin2006
> Verzonden: zondag 5 februari 2006 01:05
> Aan: ccie lab
> Onderwerp: mac access-list is denying 802.1q BPDU's on 3550 switch
>
> Hello Group,
>
> I am trying to create a mac access-list entry that will allow 802.1qBPDU's.
> I tried adding the following entry:
>
> permit any any 0x8100 0x0
>
> However bpdu's are still being blocked causing spanning tree loops.
>
> Can someone tell me if I'm using the proper ethertype or possible am not
> permitting it correctly?
>
> Thanks
>
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