AI-300 Practice Question 12: Managed Network Outbound Rule

Microsoft's table of isolation modes lists allow only approved outbound for exactly this motivation: "You want to minimize the risk of data exfiltration". In that mode you open specific destinations with outbound rules, and the docs are explicit that "adding an outbound for a service tag or FQDN is only valid when the managed VNet is configured to allow_only_approved_outbound". A public host name such as pypi.org is expressed as an FQDN rule, and the cost warning the security team asked for is documented: "FQDN outbound rules are implemented using Azure Firewall. If you use outbound FQDN rules, charges for Azure Firewall are added to your billing." (option A).

- B is wrong because allow_internet_outbound lets the managed network reach the internet generally, which is the exfiltration path the team wants closed. Adding a private endpoint for storage hardens one dependency but leaves the open outbound path untouched. - C is wrong on the rule type. Service tags name ranges of Azure services, not arbitrary public hostnames, so a service tag cannot express pypi.org, and the claim that it avoids a firewall misstates where the cost comes from, since it is the FQDN rule type that pulls in Azure Firewall. - D is wrong because the managed virtual network is created and operated by Azure Machine Learning. Managed compute automatically joins it, and you shape its traffic through isolation modes and outbound rules, not by attaching your own NSG to subnets you don't own.

Reference: Managed virtual network isolation - Azure Machine Learning