Azure Front Door and Application Gateway Deployment Order
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?
Quick Answer
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.”
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 Front Door with WAF in front of Azure Application Gateway with WAF.
The recommended deployment order is to place Azure Front Door with WAF at the edge, followed by Azure Application Gateway with WAF before the backend. This provides DDoS protection at the global level via Azure Front Door and regional web application firewall inspection via Application Gateway. Option A is incorrect because it lacks the regional WAF inspection. Option B is incorrect because Azure Front Door without WAF provides no web application firewall protection. Option C is incorrect because Application Gateway with WAF should be behind Front Door for layered defense. Therefore, Option D is correct.
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
It lacks the regional WAF inspection provided by Azure Application Gateway. Azure Front Door with WAF alone does not provide the layered defense needed.
- ✗
Azure Front Door without WAF in front of Azure Application Gateway without WAF.
Why it's wrong here
Azure Front Door without WAF provides no web application firewall protection, leaving the application vulnerable to web exploits. Application Gateway without WAF also lacks inspection.
- ✗
Azure Application Gateway with WAF in front of Azure Front Door.
Why it's wrong here
Azure Application Gateway with WAF should be placed behind Azure Front Door to provide layered defense, not in front of it. Placing Application Gateway first would not allow global DDoS protection from Front Door.
- ✓
Azure Front Door with WAF in front of Azure Application Gateway with WAF.
Why this is correct
It places Azure Front Door with WAF at the edge for global DDoS protection and web application firewall, followed by Azure Application Gateway with WAF for regional WAF inspection before the backend. This layered approach provides comprehensive security.
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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.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.