Prohibit access to switch ports with untagged vlan

[rumak18]

Hello,

i want to secure my switche from foreign access. I want to make sure, that only computers with the correct VLAN setting (tagged vlan) on his network card is able to get access to this switch. I do not want this this switch to send out untagged packets through ports. 

Is there a way for this?

[Seb Rupik · Accepted solution]

Hi there,

You will need to configure the switchport as mode trunk, and change the default native VLAN to one in a suspended state:

!
vlan 100
  name user_vlan
!
vlan 999
  name UNUSED
  state suspend
!
int gi1/0/'1
  switchport mode trunk
  switchport trunk allowed vlan add 100
  switchport trunk native vlan 999
  no shut
!

cheers,

Seb.

[rumak18]

Oh wow. Great and short. I will try it. Didn't know that you can suspend vlans.