Azure Virtual Network Manager - multiple address spaces causing issues

Question

Azure Virtual Network Manager - multiple address spaces causing issues

Kent Peter Gaardmand 0

we are attempting to use Azure Virtual Network Manager, but we have encountered an issue.

We utalize 2 address pools, one for vnet to vnet traffic and we have a secondary pool for things such intergrations to frontdoor for virtual machines and so forth.

but in Azure virtual network manager we are unable to request the VNET to create address spaces from both pools. any one know if this is possible

rvinnakota 4,760 Reputation points Moderator

2025-05-22T10:16:04.4266667+00:00

Hi @Kent Peter Gaardmand
I understand that you're facing some challenges using Azure Virtual Network Manager, specifically regarding the configuration of your address spaces. Here’s a bit of guidance:

Currently, Azure Virtual Network Manager does not automatically prevent overlapping address spaces when creating or updating virtual networks. If you're trying to register address spaces from two different pools, you'll likely face issues if those address spaces are overlapping or if the configuration isn't properly set up.

Ensure that the regions where your virtual networks reside are included in your configurations in Azure Virtual Network Manager. If a virtual network is in a region not covered by your configuration, the settings won't apply.

Are you receiving any error messages when attempting to request address spaces?
Could you please share the screenshot of the error.

Kindly let us know if the above helps or you need further assistance on this issue.
Alex Burlachenko 10,085 Reputation points

2025-05-22T15:26:59.69+00:00
Hi Kent Peter Gaardmand,

thank you for posting your question on the Microsoft Q&A portal! I really appreciate you taking the time to reach out and share your query about Azure Virtual Network Manager and multiple address spaces.

First, Azure Virtual Network Manager (AVNM) is a service that helps you manage virtual networks at scale across your Azure subscriptions. When it comes to using multiple address spaces in a virtual network, yes, it is possible to define more than one address range. According to the official Microsoft documentation, a single virtual network can have multiple address spaces, but there are some important considerations to keep in mind. You can find more details in the Azure Virtual Network documentation here: Azure Virtual Network - Address Spaces.

When you add multiple address spaces to a virtual network, all the IP ranges must be private and non-overlapping. This means you cannot use public IP ranges or have any overlaps with other networks you plan to connect to, like on-premises networks or peered virtual networks. The subnets you create will be part of one of these address spaces, so planning ahead is key to avoid conflicts. The subnet configuration guide explains this further here: Azure Subnet Planning.

If you’re using Azure Virtual Network Manager to manage these networks across different regions or subscriptions, make sure the address spaces are unique and don’t cause routing issues. AVNM helps centralize management, but the underlying networking rules still apply. For more on how AVNM handles this, check out the Azure Virtual Network Manager docs here: Azure Virtual Network Manager Overview.

I hope this helps clarify how multiple address spaces work in Azure! If you have any follow-up questions or run into specific issues while setting this up, feel free to ask I'm here to help.

Best regards, Alex P.S. If my answer help to you, please Accept my answer PPS That is my Answer and not a Comment https://ctrlaltdel.blog/
Kent Peter Gaardmand 0 Reputation points

2025-05-23T08:57:25.14+00:00

its not possible to select 2 differend pools, im fully aware that the 2 pools cant overlap.
We have 2 pools to identify server traffic from load balancers with integrations to frontdoor or other network devices.

At least its not possible from what i can tell from the Azure UI or ARM Template.
Kent Peter Gaardmand 0 Reputation points

2025-05-23T09:00:03.0066667+00:00

this answer does not address my question "Can i define multiple address spaces in Azure virtual network manager"

i cannot select or define 2 difference address pools via the ui or ARM, this causes the error message "The vnet is already associated" if i attempt to define 2 spaces with in the pool, its just consolidates the request (this i can accept, as it makes sense just to provide the larger range, rather then 2 smaller ones)
rvinnakota 4,760 Reputation points Moderator

2025-05-26T09:10:07.2466667+00:00

Hi @Kent Peter Gaardmand
Following up to see if the above suggestion was helpful. And, if you have any further query do let us know.
rvinnakota 4,760 Reputation points Moderator

2025-05-27T08:19:37.07+00:00

Hi @Kent Peter Gaardmand
Following up to see if the above suggestion was helpful. And, if you have any further query do let us know.

1 answer

Your answer

rvinnakota 4,760 Reputation points Moderator

2025-05-22T10:16:04.4266667+00:00

Hi @Kent Peter Gaardmand
I understand that you're facing some challenges using Azure Virtual Network Manager, specifically regarding the configuration of your address spaces. Here’s a bit of guidance:

Currently, Azure Virtual Network Manager does not automatically prevent overlapping address spaces when creating or updating virtual networks. If you're trying to register address spaces from two different pools, you'll likely face issues if those address spaces are overlapping or if the configuration isn't properly set up.

Ensure that the regions where your virtual networks reside are included in your configurations in Azure Virtual Network Manager. If a virtual network is in a region not covered by your configuration, the settings won't apply.

Are you receiving any error messages when attempting to request address spaces?
Could you please share the screenshot of the error.

Kindly let us know if the above helps or you need further assistance on this issue.
Kent Peter Gaardmand 0 Reputation points

2025-05-23T08:57:25.14+00:00

its not possible to select 2 differend pools, im fully aware that the 2 pools cant overlap.
We have 2 pools to identify server traffic from load balancers with integrations to frontdoor or other network devices.

At least its not possible from what i can tell from the Azure UI or ARM Template.
Kent Peter Gaardmand 0 Reputation points

2025-05-23T09:00:03.0066667+00:00

this answer does not address my question "Can i define multiple address spaces in Azure virtual network manager"

i cannot select or define 2 difference address pools via the ui or ARM, this causes the error message "The vnet is already associated" if i attempt to define 2 spaces with in the pool, its just consolidates the request (this i can accept, as it makes sense just to provide the larger range, rather then 2 smaller ones)
rvinnakota 4,760 Reputation points Moderator

2025-05-26T09:10:07.2466667+00:00

Hi @Kent Peter Gaardmand
Following up to see if the above suggestion was helpful. And, if you have any further query do let us know.
rvinnakota 4,760 Reputation points Moderator

2025-05-27T08:19:37.07+00:00

Hi @Kent Peter Gaardmand
Following up to see if the above suggestion was helpful. And, if you have any further query do let us know.

Answer 1

Hi @Kent Peter Gaardmand,

Apologies for the inconvenience caused to you,

Azure Virtual Network Manager (AVNM) currently does not natively support assigning address spaces from multiple IPAM pools to a single virtual network during creation.
I did a lab on my end and I'm also unable to associate the multiple address spaces from multiple IPAM pools.

Currently, the IP address management (IPAM) feature in Azure Virtual Network Manager is in preview. Certain features might not be supported or might have constrained capabilities.
User's image

Refer this link: https://learn.microsoft.com/en-us/azure/virtual-network-manager/how-to-manage-ip-addresses-network-manager?source=recommendations&tabs=azureportal

Kindly let us know if the above helps or you need further assistance on this issue.

Please do not forget to "Accept the answer” and “Yes” wherever the information provided helps you, this can be beneficial to other community members.

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Azure Virtual Network Manager - multiple address spaces causing issues

1 answer

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