What is Azure Load Balancer?

Azure Load Balancer is a Layer 4 load-balancing service that distributes incoming network traffic across multiple backend resources based on network-level rules. It primarily handles TCP and UDP traffic and operates at the transport layer rather than understanding application-level HTTP content. For example, suppose an application is running on three virtual machines: Client → Azure Load Balancer → VM1 / VM2 / VM3 Instead of sending all traffic to a single server, the load balancer distributes connections across the available backend instances. Azure Load Balancer supports capabilities such as: High availability Traffic distribution Health probes Automatic removal of unhealthy backend instances Public and internal load balancing Horizontal scaling scenarios A public Load Balancer can distribute internet-facing traffic, while an internal Load Balancer can distribute traffic within an Azure virtual network. It is important to distinguish Azure Load Balancer from Application Gateway. Load Balancer operates primarily at Layer 4, while Application Gateway provides Layer 7 capabilities such as HTTP/HTTPS routing, TLS termination, and web application firewall functionality. Therefore, the correct choice depends on the application's traffic type and architectural requirements.