The specified address space overlaps with subnet 'default' which has a range of '10.1.0.0/24'.

Question

_{Monday, October 22, 2018 10:26 AM}

Hello,

I tried to compute the Address range in Azure of the gateway subnet with the tool provided in Microsoft Gallery TechNet but Azure refuse the range even if I choose the prefix length /27, /28 or /29

Thanks for help

All replies (9)

_{Monday, October 22, 2018 1:59 PM ✅Answered}

Hi, 

Ok, if you want to extend the Virtual network address space you first need to remove peering. 

After that you can extend the address space and reestablish peering

_{Monday, October 22, 2018 11:18 AM}

Hi Stephane2018, 

What is the address space of your virtual network, and Gateway subnet? 

If i understand you correct you are trying to change the Gateway subnet but are getting the error above? 

/en-us/azure/virtual-network/virtual-network-manage-subnet

_{Monday, October 22, 2018 11:40 AM}

Hello T_Vuorenmaa,

Thanks for your reply

My virtual network address range (in azure) is 10.1.0.0/24 and I tried to create a Gateway Subnet but can not find the IP Address range  after test couple of methods

Thanks

_{Monday, October 22, 2018 12:41 PM}

Hi, 

If 10.1.0.0/24 is the Address space of the Virtual Network and you already have a subnet called "default" at 10.1.0.0/24 you need to either resize that or extend the Virtual networks address space to be able to create a Gateway Subnet. 

The subnet called default was created when the Virtual network was created and if you dont have any resources in the default subnet it can be removed or resized to fit the Gateway Subnet aswell.  

_{Monday, October 22, 2018 1:22 PM}

Hi,

I just have a gateway on the subnet (Connected devices) :

Type : Network interface - Ip Address 10.1.0.4 - Subnet default

_{Monday, October 22, 2018 1:26 PM}

Hi, 

That leaves you with the option to either:

• Extend the address space of the Virtual Network and then add a Gatway subnet.
• Remove the Interface on default subnet and then resize it to fit the Gateway subnet

_{Monday, October 22, 2018 1:44 PM}

Hi,

Additional information is that the virtual network in 10.1.0.0/24 is peering with an other network in 10.0.0.0/16

_{Tuesday, October 23, 2018 7:06 AM}

Hi,

I deleted the peering - changed the address space of the virtual network - create a Subnet Gateway one more time and a range has been provided automatically - I could create the subnet gateway then 

Thanks

_{Sunday, October 28, 2018 3:47 PM}

Hello,

You could have kept the "default" subnet as it was, to place your servers. For the GatewaySubnet you could have followed below steps. 

>Add a address space 10.2.0.0/24 to the same virtual network

>Create a GatewaySubnet of /27

Thanks.