When should one use an Internal load balancer?

Azure offers two flavours of load balancers – Internal and External. Internal load balancers are used to load balance the private IP segment of Cloud or VM services. These load balancers serve to connect internal services within the private virtual network and is accessible from site to site VPN connections as well. The load balances IP is still a private IP.

Refer to connectivity scenarios here

Rhipe also offers an enhanced solution for load balancing needs using KEMP. KEMP is a well-supported solution on Azure and offer greater feature set as compared to Azure native load balancer. Here is a quick reference on KEMP on Azure.