definitely Perimeter layer: The perimeter layer uses distributed denial of service (DDoS) protection to filter large-scale attacks before they can cause a denial of service for users. The network layer limits communication between resources through segmentation and access controls. link: https://docs.microsoft.com/en-us/learn/modules/secure-network-connectivity-azure/2-what-is-defense-in-depth

"The perimeter layer uses distributed denial of service (DDoS) protection to filter large-scale attacks before they can cause a denial of service for users." https://docs.microsoft.com/en-us/learn/modules/secure-network-connectivity-azure/2-what-is-defense-in-depth

It's called Perimeter for a reason...

its perimeter

Question # 10 (Multiple Choice) Which defense in depth layer uses distributed denial of service (DDoS) protection? A. Physical security layer B. Perimeter layer C. Network layer D. Application layer Item Description Answer: B Objective: 2.4 Describe Azure identity, access, and security Rationale: The perimeter layer uses distributed denial of service (DDoS) protection to filter large-scale attacks before they can cause a denial of service for users. URL: https://learn.microsoft.com/training/modules/secure-network-connectivity-azure/2-what-is-defense-in-depth https://learn.microsoft.com/en-us/certifications/resources/az-900-sample-questions

Azure DDoS Protection is not specifically part of the perimeter layer. Instead, it operates at both layer 3 (network layer) and layer 4 (transport layer) to defend against volumetric and protocol attacks. For web applications, protection at layer 7 is achieved by adding a Web Application Firewall (WAF) offering

The perimeter layer uses distributed denial of service (DDoS) protection to filter large-scale attacks before they can cause a denial of service for users.

Answer for this question is Network Layer When deployed with a web application firewall (WAF), Azure DDoS Protection protects both at the network layer (Layer 3 and 4, offered by Azure DDoS Protection) and at the application layer (Layer 7, offered by a WAF). WAF offerings include Azure Application Gateway WAF SKU and third-party web application firewall offerings available in the Azure Marketplace.

Network for me: "Azure DDoS Protection protects at layer 3 and layer 4 network layers." https://learn.microsoft.com/en-us/azure/ddos-protection/ddos-protection-overview

Perimeter layer

Perimeter is the right answer

The answer is wrong! The correct answer should be Perimeter. See this link for Defence in depth under "Perimeter": https://learn.microsoft.com/en-us/training/modules/describe-azure-identity-access-security/8-describe-defense-depth

Azure DDoS (Distributed Denial of Service) protection is implemented at the network layer. Specifically, it is designed to protect your Azure resources and applications from DDoS attacks by monitoring and mitigating malicious traffic at the network level before it reaches your virtual machines or services. This protection is deployed at Microsoft's global network edge, helping to safeguard your Azure assets from DDoS attacks that can overwhelm your network resources and disrupt your services. So, it primarily operates at the network perimeter to defend against DDoS threats.

I would of assumed Perimeter layer because in the earlier question DDoS was related to perimeter. Other than that, I honestly would not know.

Azure Distributed Denial of Service (DDoS) Protection is an example of protection that is implemented at the network layer (Layer 3 and 4) ¹. It's automatically tuned to help protect your specific Azure resources in a virtual network¹². Protection is simple to enable on any new or existing virtual network, and it requires no application or resource changes¹.

Perimeter: https://learn.microsoft.com/en-us/training/modules/describe-azure-identity-access-security/8-describe-defense-depth

Networking Layer - Is DDoS a layer 4? Layer 3 and Layer 4 DDoS Attacks Layer 3 and Layer 4 DDoS attacks are types of volumetric DDoS attacks on a network infrastructure Layer 3 (network layer), and 4 (transport layer)