- A
Azure Bastion
Why wrong: Azure Bastion provides secure RDP and SSH access to VMs directly from the Azure portal, but it does not inspect outbound traffic or provide FQDN-based filtering. It is not a firewall service.
- B
Azure Firewall
Azure Firewall is a managed, cloud-based network security service that provides inbound and outbound traffic inspection, supports FQDN-based rules, and can integrate with threat intelligence for malicious domain blocking. This matches all requirements.
- C
Network Security Group (NSG)
Why wrong: NSGs filter traffic at the subnet or NIC level based on source/destination IP addresses, ports, and protocols. They do not support FQDN-based rules, centralized logging, or threat intelligence-based filtering. They are not designed for centralized outbound inspection.
- D
Application Gateway
Why wrong: Application Gateway is a layer 7 load balancer and web application firewall (WAF) for HTTP/HTTPS traffic. It is not designed for general network-level inspection of all outbound traffic and does not provide broad FQDN-based filtering for all protocols.
Quick Answer
The answer is Azure Firewall, because it is the only Azure service that provides centralized outbound traffic inspection and filtering by fully qualified domain names (FQDN) rather than relying solely on IP addresses. Azure Firewall uses application rules to allow or deny traffic based on FQDNs, and it integrates with threat intelligence feeds to automatically block traffic to known malicious domains, meeting the security team’s requirement for logging and inspection. On the AZ-900 exam, this question tests your understanding of Azure Firewall’s role as a managed, stateful network security service, often contrasted with Network Security Groups (NSGs), which filter only by IP address and port and cannot inspect outbound traffic using FQDNs. A common trap is choosing Azure Front Door or Azure Application Gateway, but those handle inbound web traffic, not outbound inspection. Remember the memory tip: “Firewall filters FQDNs; NSGs only see IPs.”
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 runs a multi-tier application on Azure virtual machines in a virtual network. The web tier VMs are in a front-end subnet, and the database tier VMs are in a back-end subnet. Currently, outbound internet traffic from the VMs goes directly to the internet without any inspection or logging. The security team needs a centralized service to inspect all outbound traffic from the virtual network, log the destinations, and reject traffic to malicious domains based on threat intelligence feeds. The solution must also allow rules based on fully qualified domain names (FQDNs) instead of only IP addresses. Which Azure service should the security team deploy?
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
Azure Firewall
Azure Firewall is a managed, cloud-based network security service that provides centralized outbound traffic inspection, logging, and threat intelligence-based filtering. It supports application rules based on fully qualified domain names (FQDNs), allowing the security team to reject traffic to malicious domains without relying solely on IP addresses. This makes it the correct choice for inspecting and controlling outbound traffic from the virtual network.
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 Bastion
- ✓
Azure Firewall
Why this is correct
Azure Firewall is a managed, cloud-based network security service that provides inbound and outbound traffic inspection, supports FQDN-based rules, and can integrate with threat intelligence for malicious domain blocking. This matches all requirements.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Network Security Group (NSG)
Why it's wrong here
NSGs filter traffic at the subnet or NIC level based on source/destination IP addresses, ports, and protocols. They do not support FQDN-based rules, centralized logging, or threat intelligence-based filtering. They are not designed for centralized outbound inspection.
- ✗
Application Gateway
Why it's wrong here
Application Gateway is a layer 7 load balancer and web application firewall (WAF) for HTTP/HTTPS traffic. It is not designed for general network-level inspection of all outbound traffic and does not provide broad FQDN-based filtering for all protocols.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse Network Security Groups (NSGs) with Azure Firewall, assuming NSGs can perform application-layer filtering and threat intelligence-based blocking, but NSGs operate only at layers 3 and 4 (IP and port) and cannot inspect or log outbound traffic based on FQDNs or threat feeds.
Detailed technical explanation
How to think about this question
Azure Firewall uses a combination of network rules (based on IP addresses, ports, and protocols) and application rules (based on FQDNs) to control outbound traffic. It integrates with Microsoft Threat Intelligence to block traffic to known malicious domains and provides full logging via Azure Monitor and diagnostics logs. In a multi-tier application, Azure Firewall can be deployed with forced tunneling (using a default route 0.0.0.0/0 pointing to the firewall) to ensure all outbound traffic from the front-end and back-end subnets is inspected, which is not possible with NSGs alone.
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.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this AZ-900 question test?
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 Firewall — Azure Firewall is a managed, cloud-based network security service that provides centralized outbound traffic inspection, logging, and threat intelligence-based filtering. It supports application rules based on fully qualified domain names (FQDNs), allowing the security team to reject traffic to malicious domains without relying solely on IP addresses. This makes it the correct choice for inspecting and controlling outbound traffic from the virtual network.
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.
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Last reviewed: Jun 11, 2026
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.
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