Which service controls the traffic that is allowed to reach and leave AWS resources?

The correct answer is Security Groups. Security Groups act as virtual firewalls that control inbound and outbound traffic to and from AWS resources, such as Amazon EC2 instances. When you configure a Security Group, you can define rules that specify which IP address ranges or other security groups are allowed to access the resources associated with the Security Group. This allows for a highly configurable and granular level of control over network traffic.

Security Groups are stateful, meaning that if you allow an incoming request from an IP address, the response is automatically allowed, regardless of outbound rules. This makes them particularly effective for managing permissions related to traffic management for your AWS resources.

Other services mentioned have different purposes. AWS Identity and Access Management (IAM) is primarily focused on managing users, groups, and permissions to allow or deny access to AWS services and resources rather than controlling network traffic. AWS Firewall Manager is used for managing firewall rules at scale across multiple accounts and resources, but it does not directly control traffic; it's more a management layer for various firewall services, including Security Groups and AWS WAF. AWS WAF (Web Application Firewall) is specifically designed to protect web applications from common exploits and does not manage traffic for all AWS resources in the same way Security Groups do. Therefore,