Any issue if two vnet address space overlaping

Rocky Mondal 96 Reputation points


We have two vnets with same address space overlapping address space.

message is showing vnet peering is not possible in overlapping address space vnet.

Now we are planning to implement Azure firewall. My question is this any issue we will face to configure in azure firewall in overlapping address space vnets?

Azure Firewall
Azure Firewall
An Azure network security service that is used to protect Azure Virtual Network resources.
604 questions
A cloud computing platform and infrastructure for building, deploying and managing applications and services through a worldwide network of Microsoft-managed datacenters.
1,063 questions
Azure Virtual Network
Azure Virtual Network
An Azure networking service that is used to provision private networks and optionally to connect to on-premises datacenters.
2,278 questions
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2 answers

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  1. msrini-MSFT 9,271 Reputation points Microsoft Employee


    I would suggest you to have a setup done with a non-overlapping address space if you want those 2 VNETs to communicate with each other. This was you can scale your design as needed and it will reduce the complexity.

    on the side note, even when you have introduce the Azure Firewall in a hub vnet, you will not be able to peer other 2 spokes which has the same address space.


    Karthik Srinivas

    1 person found this answer helpful.
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  2. KapilAnanth-MSFT 40,256 Reputation points Microsoft Employee

    @Rocky Mondal

    Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

    I understand that you would like to know if there are any issues with having overlapping Azure VNets.

    • Overlapping Azure VNets are not an issue as long as you are not going to connect them, either via Peering or Vnet-to-Vnet VPN Connection
    • When you say you are planning to implement an Azure Firewall, this generally means that you will be deploying this into one specific VNet.
    • Now, since only one VNet is in the picture, there should not be any issue.

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



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