The correct deployment order is Azure Front Door with WAF placed in front of Azure Application Gateway with WAF. This layered architecture works because Azure Front Door operates at the global edge, providing volumetric DDoS protection at the network layer and TLS termination before traffic reaches the regional Azure Application Gateway, which then applies its own WAF for deeper, regional web application firewall inspection against common exploits like SQL injection and cross-site scripting. On the Microsoft Cybersecurity Architect exam, this scenario tests your understanding of defense-in-depth and the specific roles of Azure’s content delivery and application delivery services—a common trap is assuming a single WAF is sufficient, but the exam emphasizes that Front Door’s global WAF handles edge-level threats while Application Gateway’s WAF inspects traffic closer to the backend. Remember the memory tip: “Global first, regional last—Front Door blocks the blast, Gateway inspects the pass.”
SC-100 Design security solutions for infrastructure Practice Question
This SC-100 practice question tests your understanding of design security solutions for infrastructure. 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.
You are designing a network security architecture for an Azure application that uses Azure Front Door and Azure Application Gateway. The application must be protected from DDoS attacks and common web exploits. Application traffic should be inspected by a web application firewall (WAF) before reaching the backend. What is the recommended deployment order?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Azure Front Door with WAF in front of Azure Application Gateway with WAF.
Option B is correct because Azure Front Door should be the outermost layer for global DDoS protection and TLS termination, then Azure Application Gateway with WAF provides regional web application firewall inspection. Option A is wrong because that would inspect traffic at the gateway first, missing Front Door's global DDoS protection. Option C is wrong because placing WAF only at Front Door leaves backend traffic uninspected. Option D is wrong because Application Gateway should have WAF enabled for web exploit protection.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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 Front Door with WAF only, no Application Gateway.
Why it's wrong here
Application Gateway provides regional load balancing and additional WAF layer; Front Door alone is insufficient.
✗
Azure Front Door without WAF in front of Azure Application Gateway without WAF.
Why it's wrong here
WAF should be enabled on both for layered protection.
✗
Azure Application Gateway with WAF in front of Azure Front Door.
Why it's wrong here
Application Gateway is regional; Front Door should be outermost for global protection.
✓
Azure Front Door with WAF in front of Azure Application Gateway with WAF.
Why this is correct
Defender for Cloud supports AWS and GCP via connectors, providing unified recommendations.
Related concept
Static NAT maps one inside address to one outside address.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this SC-100 question in full detail.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related SC-100 NAT questions on configuration and troubleshooting.
Design security solutions for infrastructure — This question tests Design security solutions for infrastructure — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Azure Front Door with WAF in front of Azure Application Gateway with WAF. — Option B is correct because Azure Front Door should be the outermost layer for global DDoS protection and TLS termination, then Azure Application Gateway with WAF provides regional web application firewall inspection. Option A is wrong because that would inspect traffic at the gateway first, missing Front Door's global DDoS protection. Option C is wrong because placing WAF only at Front Door leaves backend traffic uninspected. Option D is wrong because Application Gateway should have WAF enabled for web exploit protection.
What should I do if I get this SC-100 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related SC-100 NAT questions on configuration and troubleshooting.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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 →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company uses Azure Front Door to publish a web application globally. They need to protect against DDoS attacks and web application attacks (SQL injection, XSS). Which two services should they enable in combination?
medium
A.Azure DDoS Protection Standard and Azure Firewall
B.Azure WAF on Application Gateway and Network Security Groups
C.Azure Firewall and Azure DDoS Protection Basic
✓ D.Azure DDoS Protection Standard and Azure WAF policy on Front Door
Why D: Azure DDoS Protection protects against volumetric DDoS attacks. Azure Web Application Firewall (WAF) in Front Door protects against application-layer attacks. Azure Firewall is for network-layer filtering. Network Security Groups (NSGs) are for subnet-level filtering. Azure DDoS Protection Standard is the correct tier.
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 SC-100 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 SC-100 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.