You need to configure the following for an Application Load Balancer

(1) Listener

(2) Target group

(3) Rule

Explanation

• Listener: The client connects to the listener. This is often called client side. To define a listener, a port must be provided in addition to the protocol, depending on the load balancer type. There can be many listeners for a single load balancer.
• Rule: To associate a target group to a listener, you must use a rule. Rules are made up of two conditions. The first condition is the source IP address of the client. The second condition decides which target group to send the traffic to.
• Target group: The backend servers, or server side, are defined in one or more target groups. This is where you define the type of backend you want to direct traffic to, such as EC2 instances, Lambda functions, or IP addresses. Also, a health check must be defined for each target group.