Azure-docs: Blocked at subnet

[CADbloke]

need guidance on creating the subnet. Everything I enter throws a warning, it is either not within the default subnet range or it overlaps the default subnet range. What other possible scenario is there if both of these are wrong? Also, if Bastion knows what subnet it needs, why is this step not automated?
Blocked and failed.

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• ID: 196cd28d-c7b6-9e3f-ef55-1c85d6c9be5f
• Version Independent ID: 6daf260e-526d-c5c5-50ca-c7a85e17c78a
• Content: Create an Azure Bastion host
• Content Source: articles/bastion/bastion-create-host-portal.md
• Service: bastion
• GitHub Login: @cherylmc
• Microsoft Alias: cherylmc

[AjayKumar-MSFT]

@CADbloke, Thanks for the question! We are taking a look into this and will get back to you soon.

[msrini-MSFT]

@CADbloke , can you provide me the address space of your VNET and the address prefix of the subnet that you are trying to create for Bastion

[msrini-MSFT]

@CADbloke , Any update for me on this issue?

[CADbloke]

Hi. Sorry, I got no notifications this was updated. Thanks for responding.
Private IP: 10.0.1.4
subnet: 10.0.1.0/24 (default)
subnet to create for Bastion? : NFI - that's the guidance I need. As you have probably guessed, I'm not a network devop.
If I try the same range as the default subnet I get The specified address space overlaps with subnet 'default' which has a range of '10.0.1.0/24'.
If I use range outside the default subnet I get Your subnet is not contained within the address space for this virtual network: 10.0.1.0/24.
That's when I decided Azure is even harder than building a Wix installer and I gave up.

AzureBastionSubnet
Manage subnet configuration
To associate a virtual network with a Bastion, it must contain a subnet with name AzureBastionSubnet with prefix of at least /27.

This step could be automated if it is a known thing? Well, not know to me but Bastion knows what it wants.

[CADbloke]

Sorry, you asked me for an Address Space - 10.0.1.0/24, same as the default subnet (I think).
Am I supposed to add an address space then a subnet? This could be automated, no?
The barrier to entry could do with lowering on this one.
Thanks again for responding

[msrini-MSFT]

@CADbloke ,Address space is the super set of Subnet. In your case, you have exhausted the entire address space of the VNET to a subnet and hence you are not able to create new subnet for Azure Bastion.

I would suggest you the below action plan to unblock from this issue.

Navigate to the VNET and click on address space.
Add a new address space, say 10.0.2.0/24
Now create a new subnet with 10.0.2.0/24 prefix and name it as AzureBastionSubnet.

[CADbloke]

This all worked but I still think you will get a lot less of these if you automate this step. Although .... I could be dumber than the rest ... only you could know that.

Thank you for your help. :)

... update. Just so you know my use case: Just wanted a Windows desktop machine I can remote into and run a few things that need to run in a desktop machine but can't run behind a corp firewall. Neither can normal RDP, hence my interest in Bastion. I'm not trying to build a server farm and I'm a desktop dev, not any kind of networking expert.
Cheers
Ewen

[snkancharla2002]

thanks for your help. It worked like a dream for me. I was struggling almost for 45 min to configure gateway subnet :)

[alohaninja]

Wow - this could definitely be improved from 1st time users perspective... this tripped me up... the wizard should guide users instead of telling them the generic error messages The specified address space overlaps with subnet 'default' which has a range of '10.0.1.0/24'. or To associate a virtual network with a Bastion, it must contain a subnet with name AzureBastionSubnet with prefix of at least /27.

Networking - Address Space (added 10.0.2.0/24)

Networking - Subnets (added AzureBastionSubnet)