Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A company is migrating its on-premises virtual machines (VMs) to Azure using the Infrastructure as a Service (IaaS) model. The VMs run a custom legacy application that requires specific OS-level configurations. The company's IT team wants to understand which party is responsible for applying operating system security patches after the migration. According to the shared responsibility model, who is responsible for patching the OS of the Azure VMs?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
Microsoft is fully responsible for applying OS patches to the virtual machines.
Incorrect. Microsoft is responsible for patching the underlying physical hosts and hypervisor, but not the guest OS on a customer-deployed VM. The customer has administrative access to the VM and must manage the OS.
B
Best answer
The company is responsible for patching the operating system on the virtual machines.
Correct. Even though the VMs run on Azure infrastructure, the guest OS is managed by the customer. Patching the OS is part of the customer's responsibility under the shared responsibility model for IaaS.
C
Distractor review
Responsibility is shared equally between Microsoft and the company for OS patching.
Incorrect. For IaaS, the division is clear: Microsoft patches the physical layer and hypervisor, and the customer patches the guest OS. There is no shared responsibility for the same component.
D
Distractor review
Responsibility depends on whether the VM uses Windows or Linux; Microsoft patches Windows VMs and the company patches Linux VMs.
Incorrect. Microsoft does not automatically patch the guest OS of any VM regardless of the OS type. The customer is responsible for maintaining the OS on all IaaS VMs, though Microsoft offers update management tools to assist.
Common exam trap
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Technical deep dive
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A developer is building a serverless application that requires integration with an on-premises SQL Server database for real-time data processing. The on-premises network is connected to Azure via a site-to-site VPN. Which Azure service would allow the function to securely access the on-premises database without exposing it to the public internet?
Question 2
A solutions architect is designing a storage solution for a large media company. The company needs to store video files that are accessed infrequently but must be retained for several years for compliance. Which two Azure storage options meet these requirements? (Select two.)
Question 3
A company deploys a multi-tier application using Azure virtual machines. The web tier VMs must be evenly distributed across two distinct data centers within an Azure region to avoid a single point of failure from an infrastructure outage. Which Azure construct should they use to meet this requirement?
Question 4
A company wants to enforce a set of security policies across all their Azure subscriptions. They have created several individual policy definitions. Which Azure construct should they use to group these policies together and assign them as a single package?
Question 5
A company deploys a line-of-business application on an Azure virtual machine. The IT team wants to ensure the application remains secure. According to the shared responsibility model, which of the following security tasks is the sole responsibility of the customer (the company)?
Question 6
A company develops a web API that runs on Azure App Service. The development team wants to deploy a new version of the API to a staging environment, run integration tests against it, and then gradually shift production traffic to the new version. If any issues are detected, they want to immediately roll back to the previous version without redeploying. Which Azure App Service feature should the team use to meet these requirements?
FAQ
Questions learners often ask
What does this AZ-900 question test?
Static NAT maps one inside address to one outside address.
What is the correct answer to this question?
The correct answer is: The company is responsible for patching the operating system on the virtual machines. — In the shared responsibility model for IaaS, Microsoft is responsible for the physical security of the datacenter, the network infrastructure, and the hypervisor layer. The customer retains responsibility for the guest OS, including applying security patches, managing the OS configuration, and ensuring the application runs securely. This is different from PaaS or SaaS, where Microsoft manages more of the underlying components. Since the company is using IaaS, they must manage OS patches themselves.
What should I do if I get this AZ-900 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
Discussion
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