A company deploys a new application on three Amazon EC2 instances across three Availability Zones...

Configuring Security Groups:

Security groups act as virtual firewalls for your instances to control inbound and outbound traffic.

Steps:

Go to the AWS Management Console.

Navigate to EC2.

Select "Security Groups" from the left-hand menu.

Find and select the security group associated with your EC2 instances.

Choose the "Inbound rules" tab and click "Edit inbound rules."

Add a rule to allow traffic from the security group associated with the NLB.

Type: Custom TCP (or the specific port your application uses)

Source: Select "Custom" and enter the ID of the NLB's security group.

This setup ensures that the EC2 instances accept traffic only from the NLB, enhancing security with minimal operational overhead.

AWS Security Groups