What are High availability ports in Azure Load Balancer?

Azure Standard Load Balancer helps you load-balance all protocol flows on all ports simultaneously when you're using an internal load balancer via HA Ports.

High availability (HA) ports are a type of load balancing rule that provides an easy way to load-balance all flows that arrive on all ports of an internal standard load balancer. The load-balancing decision is made per flow. This action is based on the following five-tuple connection: source IP address, source port, destination IP address, destination port, and protocol

The HA ports load-balancing rules help you with critical scenarios, such as high availability and scale for network virtual appliances (NVAs) inside virtual networks. The feature can also help when a large number of ports must be load-balanced.

The HA ports load-balancing rules are configured when you set the front-end and back-end ports to 0 and the protocol to All. The internal load balancer resource then balances all TCP and UDP flows, regardless of port number.