Azure Application Gateway FAQ

Frequently Asked Questions

What is Azure Application Gateway?

Azure Application Gateway is a web application accelerator and load balancer that enables you to manage traffic to your web applications. It offers Layer 7 load balancing capabilities, enabling you to redirect traffic based on attributes of the request, such as the HTTP headers, URI paths, or query string parameters.

What are the key features of Application Gateway?

Key features include:

  • HTTP load balancing (Layer 7)
  • SSL/TLS termination
  • Cookie-based session affinity
  • Web Application Firewall (WAF)
  • URL-based content routing
  • Host-based routing
  • Redirection capabilities
  • Connection draining
  • Auto-scaling
  • Private IP address support
How does Application Gateway differ from Azure Load Balancer?

Azure Load Balancer operates at Layer 4 (TCP/UDP) and provides high-performance, low-latency Layer 4 load balancing. Application Gateway operates at Layer 7 (HTTP/HTTPS) and provides more advanced routing capabilities, SSL termination, WAF, and URL-based routing.

Can Application Gateway handle SSL/TLS termination?

Yes, Application Gateway supports SSL/TLS termination, which offloads the encryption and decryption tasks from your backend servers. This improves performance and simplifies SSL certificate management.

What is the Web Application Firewall (WAF) in Application Gateway?

The Web Application Firewall (WAF) is a feature of Application Gateway that helps protect your web applications from common web vulnerabilities and exploits, such as SQL injection, cross-site scripting (XSS), and others. It uses the OWASP (Open Web Application Security Project) core rule set.

How does URL-based content routing work?

URL-based content routing allows you to route requests to different backend pools based on the requested URL path. For example, requests to `/images/*` could be routed to an image-serving backend pool, while requests to `/api/*` could go to an API backend pool.

Can Application Gateway scale automatically?

Yes, Application Gateway supports auto-scaling. You can configure it to automatically scale its instance count based on traffic load, ensuring high availability and performance without manual intervention.

What is a backend pool in Application Gateway?

A backend pool is a collection of virtual machines or services that Application Gateway routes traffic to. You define backend pools to group your application servers.

How do I configure health probes for my backend servers?

Application Gateway uses health probes to monitor the health of backend servers. You can configure custom health probes to specify the protocol, host, path, and status codes to check for a healthy response from your backend instances.

Where can I find more detailed documentation?

For comprehensive details, please refer to the official Azure Application Gateway documentation on Microsoft Docs.