Internal load balancing

The following diagram shows the working of an internal load balancer. You can see that the request comes from resources from Azure itself as it is not accessible on the internet. In this configuration, the load balancer is assigned a private IP address. The load balancer is only accessible within the virtual network to which it is attached. It cannot be accessed through the internet. The rest of its configuration is such as public load balancer. The load balancer can be configured with load balancing and NAT rules.

The following diagram shows how multiple load balancers can be deployed to create solutions. In this, there is a public load balancer that accepts client requests and an internal load balancer for the database tier. The database tier virtual machines are not accessible on the internet, but only through the load balancer on port 1433.