Can't create additional subnets on MX105

[woltman87]

I'm trying to create a separate VLAN for our WAPs to segment them from the management VLAN I setup. With this I plan to subnet the network I created, a /21, to a /23. When I try to save the new WAP VLAN I get the error below:

I've even switch the management VLAN from a /21 to a /22, same error. Also set both VLANs to a /21, and then it just says, "Vlan subnets cannot overlap with each other".

Is this just not possible to do on an MX/within Meraki? I'm thinking there's some interVLAN routing that needs to happen. 

[alemabrahao · Accepted solution]

the IP you want to set is not within the /23 range and if you already have another network created that overlaps setting /22 or /21 it is also not allowed, regardless of whether it is Meraki or not, this is not possible to set up.
Just try another range that doesn't overlap.

172.16.224.0/23

Host Address Range

172.16.224.1 - 172.16.225.254

[alemabrahao]

Use it to calculate. 

https://www.subnet-calculator.com/subnet.php?net_class=B

[woltman87]

So that's what I had to do: set the management as 172.16.224.0 /23, and WAP as 172.16.226.0 /23. My understanding was that the MX's IP for the whole inside network (172.16.224.0) and as the gateway for everything should be 172.16.224.1, but it appears that's not the case.