What is the main purpose of a Security Group in AWS?

The main purpose of a Security Group in AWS is to act as a virtual firewall for instances. Security Groups are used to control inbound and outbound traffic to and from AWS resources, primarily Amazon EC2 instances. They allow you to define rules that specify which traffic should be permitted and which should be denied based on various factors such as IP addresses, ports, and protocols.

When you launch an instance, you can associate it with one or more Security Groups, which apply these rules at the network interface level. This means that Security Groups help manage the security posture of the instances by controlling access to them, providing a key layer of security for resources in a cloud environment.

By allowing specific traffic while blocking others, Security Groups ensure that only authorized communications can reach your instances, enhancing the overall security and integrity of your applications running in AWS. This functionality is essential for effectively limiting access and protecting sensitive data from unauthorized access.