How to change the Allowed VLANs on a Uplink Trunk between switches?

[Slagohu]

Hi,

I want to limit the number of allowed VLANs on a trunk between two of my MS-125-1 and MS-125-2 Meraki switches.

Today the configuration on the trunk port between the switches is:

Management VLAN: 153

Native VLAN: 153

Allowed VLANs: All

The management internet is connected to MS-125-1, and the trunk I want to modify is the uplink trunk for management between MS-125-2 and MS-125-1.

I would only allow VLAN 20, 30 and 40 to pass the trunk between the switches.

• So, If I want to change the Allowed VLANs to 20, 30, and 40, should I also include the native VLAN and management VLAN 153 in the Allowed VLANs list?
• Is there any risk of losing the management connection to MS-125-2 when restricting the Allowed VLANs on the uplink trunk? ( If yes, is there a specific order to make this change so we do not lose the connection to MS-125-2 when changing the Allowed VLANs?)

[cmr]

I would include 153, though I must admit to not having tried not including the native VLAN before...  If it is not included and is required, the switch will lose connection, but then attempt to get out via the other three VLANs.  If any offer DHCP and allow Meraki cloud access then it will fix itself and change to a warning state.  You can then fix it!

[alemabrahao]

Yes, you must include the management VLAN. There is always a risk, but Meraki is intelligent enough to reverse the settings in case of a possible loss of communication.

My suggestion is to do this in a maintenance window.

[Slagohu]

"......... Meraki is intelligent enough to reverse the settings in case of a possible loss of communication" @alemabrahao do you know if this feature described some where ?

[alemabrahao · Accepted solution]

https://documentation.meraki.com/General_Administration/Cross-Platform_Content/Behavior_during_Conne...

[PhilipDAth]

You need to allow the untagged VLAN (native 153 in this case) or many things will break (like spanning tree).

[Slagohu]

It seems that all agree the VLAN 153, has to be included so that is answer to one of my questions.  But what happens after that is more unclear. I will plan for a service window and try to add the Allow VLANS on the downside of the management up-link side  first, and then on the management up-link side to see what happens.