[c-nsp] VLAN 1 troubles?

[Mark Tinka]

On 26/Aug/18 18:47, John Osmon wrote:

> I've got a 3560 switch in a lab situation that I'm looking for insight.
>
> I have a virtualization host hung off of a trunking port.  VMs on this
> platform are able to communicate over any VLAN if I'm running a 12.2
> image.
>
> As soon as I change to a 15.0 image, packets for VLAN1 no longer pass
> the switch port -- but all other VLANs do.  This is true whether the
> packets are explicitly tagged as VLAN 1, or if I leave them "native."
>
> I have means to work around the issue, but it's bugging me...
>
> Is there some esoteric change between IOS 12 and IOS 15?
> Is there something I've been doing wrong for years with IOS switches?
> Am I hitting a bug?
> Do I just need to get rid of this test switch and get something more
> modern for a lab switch?
>
>
> Switch details:
>  model:         WS-C3560G-24TS
>  working image: c3560-advipservicesk9-mz.122-25.SEE2.bin
>  failing image: c3560-ipservicesk9-mz.150-2.SE10.bin
>  port config:
>    interface GigabitEthernet0/15
>     switchport trunk encapsulation dot1q
>     switchport mode trunk

Due to the way Cisco has always treated VLAN 1, general advice over the
years has been to avoid using it for production traffic.

We don't even use it for switch management.

Mark.