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To successfully create and assign policies that involve network groups in Azure, the following permissions are required:
https://learn.microsoft.com/en-us/azure/templates/microsoft.authorization/policyassignments?pivots=deployment-language-bicep
You need the Microsoft.Network/networkManagers/networkGroups/join/action permission on the target network group in your policy. This permission allows you to add resources to that network group.
Network Contributor: Grants permissions to manage network resources, including network groups.
Resource Policy Contributor: Allows management of policy definitions and assignments.
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