Merge pull request #269326 from Blackmist/auth-limitations

adding info per PM request

Author: prmerger-automator[bot]

articles/machine-learning/how-to-identity-based-service-authentication.md

@@ -35,6 +35,17 @@ Azure Machine Learning is composed of multiple Azure services. There are multipl
 
 * You must be familiar with creating and working with [Managed Identities](../active-directory/managed-identities-azure-resources/overview.md).
 
+## Azure Container Registry supported configurations
+
+The following table lists the supported configurations when authenticating to __Azure Container Registry__, depending on the authentication method and the __public network access__ workspace flag.
+
+| Authentication method | Public network access</br>disabled | Public network access</br>enabled |
+| ---- | :----: | :----: |
+| Admin user | ✓ | ✓ |
+| Workspace system-assigned managed identity | ✓ | ✓ |
+| Workspace system-assigned and user-assigned managed identity</br>with the ACRPull role assigned to the identity |  | ✓ |
+| Compute system-assigned or user-assigned managed identity</br>with the ACRPull role assigned to the identity |  |  |
+
 ## User-assigned managed identity
 
 ### Workspace