Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
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
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
Azure Bastion
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
Best answer
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
Distractor review
Network Security Group (NSG)
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
Distractor review
Application Gateway
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 trap
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Technical deep dive
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
- CIDR notation defines the prefix length.
- Block size helps identify subnet boundaries.
- Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
- The required host count determines the smallest suitable subnet.
TExam Day Tips
- Write the block size before choosing the subnet.
- Check whether the question asks for hosts, subnets or a specific address range.
- Do not confuse /24, /25, /26 and /27 host counts.
Related practice questions
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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?
CIDR notation defines the prefix length.
What is the correct answer to this question?
The correct answer is: Azure Firewall — Azure Firewall is a fully managed cloud firewall service that allows you to create, enforce, and log application and network connectivity policies across subscriptions and virtual networks. It supports FQDN-based rules for outbound traffic, making it suitable for this scenario. Unlike NSGs, which are stateless or stateful but IP-based, Azure Firewall provides centralized control, logging, and threat intelligence integration.
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.
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