Quick Answer
The answer is that the NSG lacks an inbound rule allowing TCP 443. Even when the VM has a public IP, the web service is running, and the guest OS firewall permits HTTPS, the Network Security Group acts as Azure’s first line of defense at the subnet or NIC level. Without an explicit inbound security rule for TCP 443, all HTTPS traffic from the internet is silently dropped before it ever reaches the VM’s operating system. On the AZ-104 exam, this scenario tests your understanding of Azure’s layered security model, where NSGs filter traffic before the guest OS firewall even sees it. A common trap is assuming that because the VM’s internal firewall is open, the issue must be elsewhere—but the NSG is the most likely Azure-side culprit when an NSG inbound rule for HTTPS is not working. Memory tip: think of the NSG as the bouncer at the door; even if the party inside is ready, no one gets in without an explicit invite on the guest list.
This AZ-104 practice question tests your understanding of implement and manage virtual networking. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Users on the internet cannot access an HTTPS website hosted on VM-Web01. The VM has a public IP address, the web service is running, and the guest OS firewall allows TCP 443. What is the most likely Azure-side issue?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
The NSG does not allow inbound TCP 443
A missing or denying NSG rule on TCP 443 would block internet access to the website.
The VM uses managed disks
Why wrong: Managed disks do not block inbound HTTPS access.
Azure Backup is not enabled
Why wrong: Backup configuration does not affect HTTPS connectivity.
The storage account uses the Cool tier
Why wrong: Storage access tier is unrelated to web traffic to the VM.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The NSG does not allow inbound TCP 443
The most likely Azure-side issue is that the Network Security Group (NSG) associated with the VM's subnet or NIC does not have an inbound rule allowing TCP 443. Even if the guest OS firewall permits HTTPS and the web service is running, the NSG acts as a distributed firewall that filters traffic at the Azure network boundary. Without an explicit inbound security rule for TCP 443, all HTTPS traffic from the internet is dropped before reaching the VM.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
The NSG does not allow inbound TCP 443
Why this is correct
A missing or denying NSG rule on TCP 443 would block internet access to the website.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
The VM uses managed disks
Why it's wrong here
Managed disks do not block inbound HTTPS access.
Azure Backup is not enabled
Why it's wrong here
Backup configuration does not affect HTTPS connectivity.
The storage account uses the Cool tier
Why it's wrong here
Storage access tier is unrelated to web traffic to the VM.
Common exam traps
The trap here is that candidates often assume that because the guest OS firewall allows the port and the web service is running, the VM is fully accessible, overlooking the fact that Azure's NSG is an additional, mandatory layer of network filtering that must also permit the traffic.
Detailed technical explanation
NSGs are stateful, meaning that if you allow outbound traffic, the return traffic is automatically permitted, but inbound traffic must be explicitly allowed via security rules. Each NSG rule is evaluated by priority (lower number = higher priority), and if no rule matches, traffic is denied by default. In a real-world scenario, a common misconfiguration is allowing TCP 443 only for the source IP of a specific virtual network or Azure load balancer, inadvertently blocking all internet traffic.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Implement and Manage Virtual Networking — This question tests Implement and Manage Virtual Networking — Read the scenario before looking for a memorised answer..
The correct answer is: The NSG does not allow inbound TCP 443 — The most likely Azure-side issue is that the Network Security Group (NSG) associated with the VM's subnet or NIC does not have an inbound rule allowing TCP 443. Even if the guest OS firewall permits HTTPS and the web service is running, the NSG acts as a distributed firewall that filters traffic at the Azure network boundary. Without an explicit inbound security rule for TCP 443, all HTTPS traffic from the internet is dropped before reaching the VM.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 11, 2026
This AZ-104 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-104 exam.
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