vMX between Meraki to Azure

[Cyrus777]

I'm setting up a vMX to connect to our Azure resources following this doc: https://documentation.meraki.com/MX/MX_Installation_Guides/vMX_Setup_Guide_for_Microsoft_Azure

I picked a subnet within the vNET that my resources are located on for my Meraki vMX when I created on Azure but I get this warning on Meraki vNET address space: "Address space 'x.x.x.x/x' overlaps with address space 'x.x.x.x/x' of virtual network 'vNET-Meraki'. Virtual networks with overlapping address space cannot be peered. If you intend to peer these virtual networks, change address space 'x.x.x.x/x'.

The document mentions that I need to deploy my Azure vMX on same vNET but different subnet that prod. so I did.

Any ideas what i'm missing here? should I create this VMX in a totally different address space?

[alemabrahao]

The subnet you’ve chosen for your Meraki vMX is overlapping with the address space of your ‘vNET-Meraki’. You need to choose a completely different address space for your vMX that doesn’t overlap with 'vNET-Meraki’.

[alemabrahao]

One more question? What sbunet mask are you using? 

[Cyrus777]

so I have a /24 for my Meraki vNET (which is a test vNET works as my resource location on Azure) and I dedicated a /25 subnet under this vNET (not production) that I used it for my vmx deployment to have both under the same vNET based on document. 

[alemabrahao]

If your /25 is in the same range as the /24, it will actually overlap.

If you are in doubt, you can use this calculator.

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

[Cyrus777]

I totally understand this. but document tells me to create a subnet as SD-WAN under the same vNET and deploy the vmx on that subnet. so I did. 

I could go with a different subnet outside my vNET-MERAKI to deploy my vmx and no issues. I worried it might not work as expected if I don't follow the doc.

[alemabrahao]

Documentation is not absolute. 😉

[alemabrahao]

Maybe it will help you.

https://www.youtube.com/watch?v=Prp9HrBjG14

[MartinLL]

Just checking, but are you trying to create a new address space within the market place deployment, or do you plan on using the existing one? You need to select it manually as the market place wizard wants to create new space for you by default.

Also, the VMX deployment fails if try to deploy it to anything smaller then /24.

Deploy the vMX to a different subnet space in the VNET. If you lack space you can always go to the VNET address range and add an additonal range to provide more space.

i HIGHLY recommend that you create your own VNET and subnets within. If you let the wizard do this for you, you lose controll over the VNET and subnet object, meaning that you can not add NSG's and so such to it.