[c-nsp] Not Allowing Vlan 1 on trunk ports

[Ian Henderson]

Hitesh Vinzoda wrote on 2009-01-18:

> Is there a way to supress vlan 1 from passing from a trunk link coz i
> m not able to shutdown the L2 vlan 1.

It depends on the platform and IOS version. If it works, you'll be able to just use a 'switchport trunk allowed vlan 2,5,6-8' or similar. If that command fails, it will tell you to include VLAN 1 and 1002-1005.

For example, this is on an a 2950-24 running 12.1(9)EA1. A more modern IOS would work as intended (only trunking VLAN 2, 3, 4, 5):

switch-1(config)#int f0/1
switch-1(config-if)#switchport trunk allowed vlan 2-5
Command rejected: Bad VLAN allowed list.
VLANs 1,1002-1005 are required.
switch-1(config-if)#



Rgds,



- I.

--
Ian Henderson, CCIE #14721
Senior Network Engineer, iiNet Limited