The correct answer is Azure Virtual Network with subnets and Network Security Groups. This solution works because a Virtual Network lets you segment resources into different subnets within the same Azure region, meeting the low-latency requirement, while Network Security Groups act as a stateful firewall to filter traffic at the subnet level. By applying an NSG to the database subnet with a rule that allows inbound traffic only from the web tier’s subnet (using source IP or a service tag like VirtualNetwork), you achieve the necessary tier isolation and restricted access. On the AZ-900 exam, this scenario tests your understanding of basic network segmentation and security—a common trap is confusing NSGs with Azure Firewall or thinking different VNets are required for isolation within the same region. Remember the memory tip: “Subnets split, NSGs protect” to recall that subnets provide logical separation while NSGs enforce the rules.
AZ-900 Describe Azure architecture and services Practice Question
This AZ-900 practice question tests your understanding of describe azure architecture and services. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 deploys a multi-tier web application on Azure. The web tier and database tier must be in the same region for low latency, but the database tier must be in a different subnet and have restricted network access from the web tier only. Which Azure network solution should they use?
Azure Virtual Network with subnets and Network Security Groups
Correct. A VNet with subnets isolates the tiers, and NSGs enable rules to allow traffic only from the web tier to the database tier on specific ports.
B
Azure Application Gateway
Why wrong: Incorrect. Application Gateway is a layer-7 load balancer and Web Application Firewall, not used for subnet isolation or network access control between subnets.
C
Azure Load Balancer
Why wrong: Incorrect. Load Balancer distributes traffic at layer-4 but does not provide subnet segmentation or granular network rules between tiers.
D
Azure Traffic Manager
Why wrong: Incorrect. Traffic Manager is a DNS-based traffic routing service for global load balancing, not for VNet-level network segmentation.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Azure Virtual Network with subnets and Network Security Groups
Azure Virtual Network (VNet) with subnets and Network Security Groups (NSGs) is the correct solution because it allows you to create isolated subnets for the web and database tiers within the same region, ensuring low latency. NSGs can then be applied to the database subnet to restrict inbound traffic exclusively from the web tier's subnet using source IP or service tag rules, providing the required network segmentation and access control.
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.
✓
Azure Virtual Network with subnets and Network Security Groups
Why this is correct
Correct. A VNet with subnets isolates the tiers, and NSGs enable rules to allow traffic only from the web tier to the database tier on specific ports.
Related concept
Read the scenario before looking for a memorised answer.
✗
Azure Application Gateway
Why it's wrong here
Incorrect. Application Gateway is a layer-7 load balancer and Web Application Firewall, not used for subnet isolation or network access control between subnets.
✗
Azure Load Balancer
Why it's wrong here
Incorrect. Load Balancer distributes traffic at layer-4 but does not provide subnet segmentation or granular network rules between tiers.
✗
Azure Traffic Manager
Why it's wrong here
Incorrect. Traffic Manager is a DNS-based traffic routing service for global load balancing, not for VNet-level network segmentation.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse load balancing or application delivery services (like Application Gateway or Load Balancer) with network security and segmentation, assuming they can restrict access between tiers, when in fact NSGs are the correct Azure service for subnet-level traffic filtering.
Detailed technical explanation
How to think about this question
Under the hood, NSGs contain a set of security rules that are evaluated in priority order (lowest number first) for inbound and outbound traffic, supporting both source and destination IP addresses, ports, and service tags like 'VirtualNetwork' or 'AzureLoadBalancer'. In a multi-tier architecture, you can create a custom rule on the database subnet NSG that allows traffic only from the web tier's subnet prefix (e.g., 10.0.1.0/24) on the database port (e.g., 1433 for SQL Server), while denying all other inbound traffic by default. A real-world scenario is a finance app where the web tier must query a SQL database with minimal latency, but the database must be hardened against lateral movement from other subnets or the internet.
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 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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this AZ-900 question in full detail.
Describe Azure architecture and services — This question tests Describe Azure architecture and services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Azure Virtual Network with subnets and Network Security Groups — Azure Virtual Network (VNet) with subnets and Network Security Groups (NSGs) is the correct solution because it allows you to create isolated subnets for the web and database tiers within the same region, ensuring low latency. NSGs can then be applied to the database subnet to restrict inbound traffic exclusively from the web tier's subnet using source IP or service tag rules, providing the required network segmentation and access control.
What should I do if I get this AZ-900 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This AZ-900 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-900 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.