[APIM] addressPrefix subnet requirement

Author: gitName

articles/api-management/inject-vnet-v2.md

@@ -68,6 +68,8 @@ The subnet needs to be delegated to the **Microsoft.Web/hostingEnvironments** se
 
 For more information about configuring subnet delegation, see [Add or remove a subnet delegation](../virtual-network/manage-subnet-delegation.md).
 
+[!INCLUDE [api-management-virtual-network-address-prefix](../../includes/api-management-virtual-network-address-prefix.md)]
+
 ### Permissions
 
 You must have at least the following role-based access control permissions on the subnet or at a higher level to configure virtual network integration:

articles/api-management/integrate-vnet-outbound.md

@@ -63,6 +63,9 @@ The subnet needs to be delegated to the **Microsoft.Web/serverFarms** service.
 
 For more information about configuring subnet delegation, see [Add or remove a subnet delegation](../virtual-network/manage-subnet-delegation.md).
 
+[!INCLUDE [api-management-virtual-network-address-prefix](../../includes/api-management-virtual-network-address-prefix.md)]
+
+
 ### Permissions
 
 You must have at least the following role-based access control permissions on the subnet or at a higher level to configure virtual network integration:

includes/api-management-virtual-network-address-prefix.md

@@ -0,0 +1,25 @@
+---
+author: dlepow
+ms.service: azure-api-management
+ms.topic: include
+ms.date: 11/21/2024
+ms.author: danlep
+---
+
+### addressPrefix property
+
+To configure networking in the Premium v2 tier, the `addressPrefix` subnet property is required and must be set to a valid CIDR block. 
+
+If you configure the subnet using the Azure portal, the subnet sets an `addressPrefixes` (plural) property consisting of a list of address prefixes. However, the API Management service currently requires a single CIDR block as the value of the `addressPrefix` property. 
+
+To create or update a subnet with the `addressPrefix` property, use a tool such as Azure PowerShell, an Azure Resource Manager template, or the [REST API](/rest/api/virtualnetwork/subnets/create-or-update). For example, update a subnet using the [Set-AzVirtualNetworkSubnetConfig](/powershell/module/az.network/set-azvirtualnetworksubnetconfig) Azure PowerShell cmdlet:
+
+```powershell
+$virtualNetwork = "MyVirtualNetwork"
+$subnetName = "apimSubnet"
+$addressPrefix = "10.0.3.0/24"
+
+Set-AzVirtualNetworkSubnetConfig -Name $subnetName -VirtualNetwork $virtualNetwork -AddressPrefix $addressPrefix
+
+$virtualNetwork | Set-AzVirtualNetwork
+```