native vlan allowed

[Lennotoecom]

Hello all,

I have a question about the native vlan feature on trunks

a simple configuration

interface fa0/0

switchport trunk native vlan 4

switchport trunk allowed vlan 5,6

in all the labs I could do, this config prevented the native vlan from working on a trunk, but still, out there are a lot of people that claim

that native vlan does not have to be explicitly allowed and that even in the above configuration the trunk works with all vlans.

As I understand correctly this is even cisco's official view, which is wrong!

please, help me figure this out?

[Dennis Mink]

I would agree with your statement,  I also cannot believe people are still using that wretched native vlan as it confuses the hell out of most people, it breaks more than it fixes  /rant off.

that statement above is preventing VLAN 4 to go across the trunk, because you are not allowing it. even though you are forcing vlan 4 not to be tagged by defining it the native vlan, it is still not allowed.

if you were to make it switchport trunk allowed vlan 4-6  , on both ends of the trunk, it should work.