Azure provides two constructs to provision load balancers. It provides a level-4 load balancer that works at the transport layer within TCP OSI stack and a level-7 load balancer that works at application and session level.
Although both application gateways and load balancer provide basic features of balancing the load, they serve different purposes. There are use cases in which application gateway makes more sense to deploy compared to load balancer.
Application gateway provides the following features that are not available in the Azure load balancers:
- Web application firewall: This is an additional firewall on top of operating system firewall and has the capability to peek into incoming messages. This help in identifying and protecting from common web-based attacks such as SQL injection, cross-site scripting attacks, and session hijacks.
- Cookie-based session...
