Application Gateway (AGW) is a web traffic manager for your web applications (one or multiple)
With AGW, on top of load balancing your workloads, you can make routing decisions based on URI path or host headers.
It can be used to do TLS/SSL termination. TLS/SSL termination can be useful to allow unencrypted traffic between AGW and backend servers saving some of the processing load needed to encrypt and decrypt said traffic. Application Gateway also supports end-to-end TLS/SSL encryption.
It includes a web application firewall called Web application firewall (WAF) that protects your workload from common exploits like SQL injection attacks or cross-site scripting attacks, to name a few.
It provides an application delivery controller (ADC) as a service, offering various Layer 7 load-balancing capabilities. Use it to optimize web farm productivity by offloading CPU-intensive SSL termination to the gateway.
How is Azure Application Gateway used?
It primarily provides a complete, cloud-based, secure, and scalable load-balancing solution for web applications and services. Some ways to use it include;
Deliver and manage load-balancing solutions for websites, web applications or internet-based services
Provide load balancing for internal web-enabled/powered services
Deliver cookie-based session affinity service
Enable SSL offloading service that takes the encryption/decryption burden out of the primary web server
Application gateway end-to-end communication
Application Gateway Features
Application Gateway includes the following features
Secure Sockets Layer (SSL/TLS) termination
Autoscaling
Zone redundancy
Static VIP
Web Application Firewall
Ingress Controller for AKS
URL-based routing
Multiple-site hosting
Redirection
Session affinity
Websocket and HTTP/2 traffic
Connection draining
Custom error pages
Rewrite HTTP headers and URL
Sizing
Application Gateway Configuration
For Application Gateway, there are two SKUs that are available – v1 SKUs and v2 SKUs. Each of these SKUs has two tiers – Standard and Web Application Firewall (WAF). So, Azure offers four different tiers for application gateway.
Standard
Standard v2
WAF
WAF v2
Feature comparison between v1 SKU and v2 SKU
