AWS Technical Essentials Practice 2025 – The All-in-One Guide to Mastering Your Exam Essentials!

A security group in AWS functions as a virtual firewall specifically designed to control inbound and outbound traffic for Amazon EC2 instances. It allows users to define rules that specify which traffic is permitted to reach the instances, based on factors such as IP address, protocol, and port number. This provides a crucial layer of security, as it allows organizations to limit access to their resources and only allow connections from trusted sources. By configuring security groups, users can ensure that their EC2 instances are protected from unauthorized access while enabling necessary traffic for intended services.

The other options don't align with the primary function of a security group. A security group is not involved in billing management, uptime monitoring, or data backup procedures. Instead, AWS provides other specific tools and services to address those needs. For example, AWS Billing Dashboard manages billing, Amazon CloudWatch can monitor service uptime, and services like AWS Backup handle data backup procedures.