Native Vlans and traffic

[milibor74]

Hi Guy's,

So I am trying to understand native Vlans in a particular environment. So lets assume my core and switch have trunks with native vlan 111 and allowed vlan 10,20,30)

Now for some weird client request I was asked to create trunks on my switch with a native vlan of 10

So now on the switch all my ports are trunked as Native 10, allowed 10,20,30 except the uplink with the core that stays the same. 

The client wants to be able to bring up nodes through untagged traffic on vlan 10 through an ESXI environment(Nutanix to be specific).

My question is: Can the untagged traffic from vlan 10 go to my core? I believe it can but I would like confirmation.

Would there be a way to prevent it from going to the core short of removing vlan 10 from the trunk to the core? 

            Servers --------- Trunk(native10, all 10,20,30) - - - - - - - - - - --Switch  --------------Trunk(native111), allowed 10,20,30) ---------- Core

Thanks

[Jon Marshall]

It can go to the core switch but on that uplink the traffic will be tagged because it is not the native vlan on that link.

In terms of preventing it getting to the core the easiest way would be, as you say, to not allow it on the trunk link and the easiest way is often the best :)

Jon