📖 What is Azure Application Gateway?
Azure Application Gateway is a Layer 7 load balancer delivering web application performance, reliability, and security. It distributes incoming web traffic across multiple backend servers, offering features like SSL offloading, URL-based routing, and integrated Web Application Firewall (WAF) capabilities for enhanced protection.
"Understand the distinction between Application Gateway and Azure Load Balancer. Application Gateway operates at Layer 7, providing HTTP/HTTPS-specific features, while Azure Load Balancer functions at Layer 4. Exam questions frequently test this difference and WAF integration."
📚 Certification: Microsoft Azure Fundamentals (AZ-900)
🔑 What are the Key Concepts of Azure Application Gateway?
- ▸ Application Gateway operates at Layer 7 (HTTP/HTTPS), enabling advanced routing based on URL paths, hostnames, and other request properties.
- ▸ SSL offloading is a key feature, decrypting traffic at the gateway to reduce the load on backend servers and simplify certificate management.
- ▸ Integrated Web Application Firewall (WAF) protects web applications from common exploits like SQL injection and cross-site scripting (XSS).
- ▸ Session affinity (cookie-based affinity) ensures requests from the same user are routed to the same backend server for stateful applications.
- ▸ It supports multiple backend pools, allowing traffic distribution across different server farms based on defined rules and health probes.
🎯 How does Azure Application Gateway appear on the AZ-900 Exam?
You may be asked to identify the Azure service best suited for protecting a web application from common web attacks, considering features like WAF and SSL offloading.
A scenario might describe a requirement to route traffic to different backend servers based on the URL path – determine which Azure service provides this capability.
Expect questions about choosing between Azure Application Gateway and Azure Load Balancer based on application requirements (HTTP/HTTPS vs. TCP/UDP).
❓ Frequently Asked Questions
When would I choose Application Gateway over Azure Load Balancer?
Choose Application Gateway for web applications needing Layer 7 features like URL-based routing, SSL offloading, and WAF. Load Balancer is better for non-HTTP/HTTPS traffic or simple load balancing.
How does the WAF component of Application Gateway work?
The WAF uses rule sets (managed by Microsoft or custom) to inspect incoming HTTP(S) traffic and block malicious requests based on known attack patterns. It helps protect against OWASP Top 10 vulnerabilities.
What are health probes and why are they important?
Health probes periodically check the availability of backend servers. If a server fails a probe, Application Gateway stops sending traffic to it, ensuring high availability and preventing user errors.