- A
Enable Web Application Firewall (WAF) on the Application Gateway to block non-Front Door traffic.
Why wrong: WAF inspects application layer traffic, not source IP restrictions.
- B
Configure Azure Front Door Premium with Private Link origin to the Application Gateway.
Private Link ensures traffic from Front Door to the origin is private and only from Front Door.
- C
Add a network security group (NSG) on the Application Gateway subnet to deny all traffic except from Front Door's IP ranges.
Why wrong: NSG on the Application Gateway subnet would block traffic to the gateway itself, but the Application Gateway still listens on its public IP; the NSG would block traffic to the subnet, but the gateway's public IP is not in the subnet.
- D
Use Azure Front Door geo-filtering to block all countries except the home country.
Why wrong: Geo-filtering does not restrict to Front Door IPs; it blocks by geographic location.
Quick Answer
The correct answer is to configure Azure Front Door Premium with Private Link origin to the Application Gateway. This solution enforces a defense-in-depth approach by ensuring that traffic from Front Door to the origin travels exclusively over the Microsoft backbone via a private endpoint, completely bypassing the public internet and eliminating exposure to arbitrary source IPs. Even if access restrictions on the Application Gateway are misconfigured or bypassed, the Private Link connection guarantees that only validated Front Door traffic can reach the origin, closing the gap left by IP-based allowlists alone. On the AZ-500 exam, this scenario tests your understanding of network segmentation and secure origin access, often appearing as a trap where candidates mistakenly rely solely on IP restrictions or WAF rules. Remember the key distinction: IP restrictions are a perimeter control, but Private Link provides identity-based, network-level isolation. A useful memory tip is "Private Link plugs the IP gap"—it adds a private, unrouteable connection that no external source can spoof.
AZ-500 Secure networking Practice Question
This AZ-500 practice question tests your understanding of secure networking. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
You are a security architect for a global company. The company uses Azure Front Door to publish web applications. You need to ensure that only traffic from Azure Front Door's backend IP ranges can reach the origin servers. The origin servers are behind Azure Application Gateway. You have already configured Access Restrictions on the Application Gateway to allow only Azure Front Door's backend IP ranges. However, you discover that the Application Gateway is still receiving traffic from other sources. You need to implement a defense-in-depth approach to ensure only Azure Front Door traffic reaches the origin. What should you do?
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
Configure Azure Front Door Premium with Private Link origin to the Application Gateway.
Option A is correct: Private Link with Front Door Private Endpoint ensures traffic from Front Door to the origin goes over the Microsoft backbone and is not exposed to the internet. This, combined with Access Restrictions, provides defense-in-depth. Option B is incorrect because WAF does not restrict source IPs. Option C is incorrect because the origin is already behind Application Gateway, and adding NSG at the subnet does not prevent traffic from other sources that are allowed through Application Gateway. Option D is incorrect because geo-filtering does not restrict to Front Door IPs.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable Web Application Firewall (WAF) on the Application Gateway to block non-Front Door traffic.
Why it's wrong here
WAF inspects application layer traffic, not source IP restrictions.
- ✓
Configure Azure Front Door Premium with Private Link origin to the Application Gateway.
Why this is correct
Private Link ensures traffic from Front Door to the origin is private and only from Front Door.
Related concept
CIDR notation defines the prefix length.
- ✗
Add a network security group (NSG) on the Application Gateway subnet to deny all traffic except from Front Door's IP ranges.
Why it's wrong here
NSG on the Application Gateway subnet would block traffic to the gateway itself, but the Application Gateway still listens on its public IP; the NSG would block traffic to the subnet, but the gateway's public IP is not in the subnet.
- ✗
Use Azure Front Door geo-filtering to block all countries except the home country.
Why it's wrong here
Geo-filtering does not restrict to Front Door IPs; it blocks by geographic location.
Common exam traps
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.
Detailed technical explanation
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.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
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.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related AZ-500 subnetting questions on CIDR, address ranges, and subnet selection.
- →
Secure networking — study guide chapter
Learn the concepts, then practise the questions
- →
Secure networking practice questions
Targeted practice on this topic area only
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AZ-500 practice test guide
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FAQ
Questions learners often ask
What does this AZ-500 question test?
Secure networking — This question tests Secure networking — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Configure Azure Front Door Premium with Private Link origin to the Application Gateway. — Option A is correct: Private Link with Front Door Private Endpoint ensures traffic from Front Door to the origin goes over the Microsoft backbone and is not exposed to the internet. This, combined with Access Restrictions, provides defense-in-depth. Option B is incorrect because WAF does not restrict source IPs. Option C is incorrect because the origin is already behind Application Gateway, and adding NSG at the subnet does not prevent traffic from other sources that are allowed through Application Gateway. Option D is incorrect because geo-filtering does not restrict to Front Door IPs.
What should I do if I get this AZ-500 question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related AZ-500 subnetting questions on CIDR, address ranges, and subnet selection.
What is the key concept behind this question?
CIDR notation defines the prefix length.
About these practice questions
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Last reviewed: Jun 20, 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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