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.”
⚠ Common exam trap
SC-100 often tests the order of layered security services — candidates incorrectly place Application Gateway in front of Front Door, forgetting that Front Door is the global entry point and must be the first hop.
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 architecture places Azure Front Door with WAF at the global edge to absorb DDoS and block common web exploits close to the client, then routes traffic to Azure Application Gateway with WAF for regional, path-based, and application-layer protection before reaching the backend. This layered approach provides defense in depth and satisfies the requirement that traffic be inspected by a WAF before reaching the backend.
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
Placing WAF only at Azure Front Door leaves Application Gateway without inline inspection, so traffic reaching the backend bypasses the second WAF tier the scenario requires. Front Door's WAF is tempting because it filters at the global edge, which suits internet-facing protection for a single ingress point without a regional gateway layer.
- ✗
Azure Front Door without WAF in front of Azure Application Gateway without WAF.
Why it's wrong here
Neither tier runs a WAF, so common web exploits reach the backend uninspected, violating the inspection requirement. Front Door and Application Gateway both offer WAF, and placing WAF on Front Door alone would be correct when Application Gateway is omitted or used purely for regional load balancing without inspection.
- ✗
Azure Application Gateway with WAF in front of Azure Front Door.
Why it's wrong here
Application Gateway terminates traffic first, so its WAF inspects before Front Door, but Front Door is the global entry point and must precede the regional gateway; this order also exposes the gateway directly. It is tempting because Application Gateway WAF is a valid edge control when Front Door is absent.
- ✓
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 and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Microsoft exam blueprint
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