[c-nsp] Switch mac address appearing in a VLAN going through it

Ian Dickinson iand at eng.pipex.net
Wed Dec 14 06:37:26 EST 2005


Gert Doering wrote:
> Hi,
> 
> On Wed, Dec 14, 2005 at 10:25:02AM +0000, Kristofer Sigurdsson wrote:
>>Am I mistaken in believing that if a VLAN only goes "through" a
>>switch, the switch's mac address shouldn't appear in the mac address
>>table of other switches (on that VLAN)?
> 
> What you see is spanning tree packets - that are sourced from the
> neighbouring switch (in your case: the 3550).

Given that spanning-tree is killed by bpdufilter and CDP is disabled,
the likely remaining options are VTP or L2 Loopback packets.

vtp mode off ! would be nice on more platforms
vtp mode transparent ! otherwise

interface Foo
 no keepalive

are the things to try...
-- 
Ian Dickinson
Development Engineer
PIPEX
ian.dickinson at pipex.net
http://www.pipex.net

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