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[VLAN] Question on SMC switches and same MAC addr for different VLANs.

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On Mon, Oct 30, 2006 at 04:47:28PM -0800, Ben Greear wrote:
> I'm finally on the receiving end of a vlan problem :)
Wut?
/me checks mail headers... Is this really Ben?

> I want to be able to use multiple VLANs with the same MAC
> addr through an SMC switch.  But, it disables traffic
> because it thinks we have a loop or something like that.

Well, if you have SVL and the mac-addressess are on different
ports, it will be a kind of loop.

> I know there is a way to disable this on (most?) cisco
> switches, and I'm hoping it can be done on SMC as well.

We have this in one of our firewall port setting on a cisco:
interface GigabitEthernet2/43
 description leetsystem_eth1
 no ip address
 flowcontrol receive desired
 switchport
 switchport access vlan 666
 switchport trunk allowed vlan 1111,2222,3333
 switchport mode trunk
 spanning-tree portfast trunk
 spanning-tree bpduguard enable
end

But this is a really big switch with IVL
The essence is to use portfast, which declares a port is an endpoint instead of
a possible peer. In case of trunks the "trunk" keyword is obligatory.
BTW: this is IOS and not the other cisco OS.
bpduguard is an option to disable the port as soon as is clear that it is not
an endpoint, but really a bridge that does spanning-tree.

> If anyone knows the cisco and/or SMC methods of letting
> multiple VLAN devices with the same MAC communicate, please
> let me know.

Maybe you should use a linksys wrt54g, they have switches that do some kind of
IVL if I am right... It allows for the same mac-address to appear on different
ports but only in different vlans. (they call it "cloning")

> For what it's worth, Netgear switches work out of the box...

Hmmmm, all netgear switches? And what is their behaviour? Are they all IVL, or
are they just not guarding loops?

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