- A
The service endpoint for Microsoft.Sql was not enabled on the subnet before creating the firewall rule
The service endpoint must be enabled on the subnet before or concurrently with the firewall rule. If enabled after, the rule may not work until it is updated or re-created.
- B
The SQL server's firewall also has a rule allowing all Azure services, which overrides the VNet rule
Why wrong: Allowing all Azure services provides broader access, not less; it would not cause an authorization error.
- C
The virtual machine's operating system firewall is blocking outbound traffic
Why wrong: While possible, OS firewall issues typically produce different error messages (e.g., connection timeout) and are less specific to the service endpoint scenario.
- D
The subnet's NSG is blocking outbound traffic to Azure SQL
Why wrong: An NSG blocking outbound traffic would cause a similar issue, but the most likely cause related to the described configuration is the service endpoint not being properly enabled.
Quick Answer
The answer is that the service endpoint for Microsoft.Sql was not enabled on the subnet before creating the firewall rule. This causes authorization failures because Azure SQL’s virtual network rule validation occurs at rule creation time; if the service endpoint is missing, the rule is stored but never activated, so traffic from the subnet is still treated as public internet traffic and blocked by the firewall. On the Microsoft Azure Security Engineer Associate AZ-500 exam, this scenario tests your understanding of the dependency chain between service endpoints and VNet firewall rules—a common trap is assuming the rule alone is sufficient. Remember the order: first enable the service endpoint on the subnet, then add the VNet rule to the SQL server firewall. A simple memory tip is “Endpoint first, rule second—otherwise, your connection is rejected.”
AZ-500 Secure networking Practice Question
This AZ-500 practice question tests your understanding of secure 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.
A company has an Azure virtual network with a subnet that hosts Azure virtual machines. They want to restrict access to an Azure SQL Database so that only traffic originating from that specific subnet is allowed. They have enabled a service endpoint for Microsoft.Sql on the subnet and configured the SQL server firewall to allow only that subnet's virtual network rule. However, connections from the VMs to the SQL database are failing with an authorization error. What is the most likely cause?
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.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The service endpoint for Microsoft.Sql was not enabled on the subnet before creating the firewall rule
The most likely cause is that the service endpoint for Microsoft.Sql was not enabled on the subnet before the virtual network (VNet) firewall rule was created on the SQL server. When a VNet rule is added to the SQL server firewall, Azure validates that the specified subnet has a service endpoint for Microsoft.Sql enabled. If the endpoint is not enabled at the time the rule is created, the rule will be created but will not be effective, and traffic from the subnet will not be recognized as originating from the VNet, resulting in authorization errors. The service endpoint must be enabled first to ensure the subnet's traffic is routed through the Azure backbone and correctly identified by the SQL server firewall.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The service endpoint for Microsoft.Sql was not enabled on the subnet before creating the firewall rule
Why this is correct
The service endpoint must be enabled on the subnet before or concurrently with the firewall rule. If enabled after, the rule may not work until it is updated or re-created.
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 SQL server's firewall also has a rule allowing all Azure services, which overrides the VNet rule
Why it's wrong here
Allowing all Azure services provides broader access, not less; it would not cause an authorization error.
- ✗
The virtual machine's operating system firewall is blocking outbound traffic
Why it's wrong here
While possible, OS firewall issues typically produce different error messages (e.g., connection timeout) and are less specific to the service endpoint scenario.
- ✗
The subnet's NSG is blocking outbound traffic to Azure SQL
Why it's wrong here
An NSG blocking outbound traffic would cause a similar issue, but the most likely cause related to the described configuration is the service endpoint not being properly enabled.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume creating a VNet firewall rule is sufficient on its own, without realizing that the service endpoint must be enabled on the subnet first for the rule to be effective.
Trap categories for this question
Similar concept trap
An NSG blocking outbound traffic would cause a similar issue, but the most likely cause related to the described configuration is the service endpoint not being properly enabled.
Scenario analysis trap
While possible, OS firewall issues typically produce different error messages (e.g., connection timeout) and are less specific to the service endpoint scenario.
Detailed technical explanation
How to think about this question
Service endpoints for Microsoft.Sql work by adding the subnet's IP prefix to the SQL server's firewall as a virtual network rule, but only after the endpoint is enabled on the subnet. The endpoint ensures that traffic from the subnet to Azure SQL is routed via the Azure backbone network, preserving the source IP as the private IP of the VM, which the SQL server then matches against the VNet rule. If the endpoint is enabled after the VNet rule is created, the rule remains in an 'Inactive' state until the endpoint is enabled, and traffic will be denied until the rule becomes active.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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Secure networking — study guide chapter
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FAQ
Questions learners often ask
What does this AZ-500 question test?
Secure networking — This question tests Secure networking — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The service endpoint for Microsoft.Sql was not enabled on the subnet before creating the firewall rule — The most likely cause is that the service endpoint for Microsoft.Sql was not enabled on the subnet before the virtual network (VNet) firewall rule was created on the SQL server. When a VNet rule is added to the SQL server firewall, Azure validates that the specified subnet has a service endpoint for Microsoft.Sql enabled. If the endpoint is not enabled at the time the rule is created, the rule will be created but will not be effective, and traffic from the subnet will not be recognized as originating from the VNet, resulting in authorization errors. The service endpoint must be enabled first to ensure the subnet's traffic is routed through the Azure backbone and correctly identified by the SQL server firewall.
What should I do if I get this AZ-500 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 11, 2026
This AZ-500 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-500 exam.
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