NSG creation using Powershell

Question

Hi

I have been working on creating NSG using powershell.

I am using New-AzNetworkSecurityRuleConfig to define rule parameters and then using it in New-AzNetworkSecurityGroup to create NSG

However, defining CIDR values for "SourceAddressPrefix" in a powershell variable giving me "Invalid address prefix"

It looks like it is not expecting string value, I tried using different ways like

$saddressprefix = "10.10.10.1/29"

$saddressprefix = @("10.10.10.1/29")

[String[]]$saddressprefix = "10.10.10.1/29" and using it $saddressprefix[0] in the rule config

But none of them work and it fails with invalid address prefix error.

Although defining static CIDR value in rule config does work fine but I want to use variable for more flexibility

Looking for some assistance on this.

PS: defining $saddressprefix = 10.10.10.1/29 stores 0 value in the variable

Answer 1

Hello WinTechie,

You need to be utilizing the proper CIDR structure:

$sap = @("10.10.10.0/29")
$rule1 = New-AzNetworkSecurityRuleConfig -Name rdp-rule -Description "Allow RDP" -Access Allow -Protocol Tcp -Direction Inbound -Priority 100 -SourceAddressPrefix $sap -SourcePortRange * -DestinationAddressPrefix * -DestinationPortRange 3389
$nsg = New-AzNetworkSecurityGroup -ResourceGroupName "cloudaen-test" -Location "eastus" -Name "nsg" -SecurityRules $rule1

Note that I used 10.10.10.0/29 when setting up the $sap variable. I'd recommend replacing "cloudaen-test" with your RG name.

Hope this helps.

How to (for future use):

Azure NSG Creation Error - Invalid Address Prefix - PowerShell

https://www.cloudaen.com/blogs/view/nsg_creation_error

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If this is helpful please accept answer.

Answer 2

Hi @WinTechie ,

I'm not sure what you want to achieve. In my opinion 10.10.10.1 is a host IP (the first one) in the 10.10.10.0/29 network.

How did you define the virtual network and the related subnet(s)?

If you want to define one host as SourceAddressPrefix than it should be 10.10.10.1/32.

If you want to define a n address range than it should be 10.10.10.0/29

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(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)

Regards

Andreas Baumgarten