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

[Kristofer Sigurdsson]

Hi,

Gert, Ian, thanks for the advise...

Comments inline.

2005/12/14, Ian Dickinson <iand at eng.pipex.net>:
> 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).

Shouldn't "spanning-tree portfast" disable spanning-tree on the
interface?  Also, it has bpdu filters *and* spanning-tree is disabled
on the VLAN.

>
> 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

I might try these - for the time being, I did a workaround (made the
3550 port a routed port).  I'll check this during the next
maintainance window. :)

Thanks for the feedback,
Kristofer