AWS (Amazon Web Services) Certification Practice Exam

What is the primary function of Security Groups in AWS networking?

1. To control network access on a VPC level

2. To manage routing tables

3. To work at the instance level to measure traffic

4. To automate scaling of resources

The correct answer is: To work at the instance level to measure traffic

The primary function of Security Groups within AWS networking is to act as a virtual firewall for your instances, controlling inbound and outbound traffic at the instance level. Security Groups define a set of rules that specify which types of traffic are allowed or denied for the instances they are associated with. This means that, for any given instance, you can specify which IP addresses or ranges may communicate with it and on which ports, as well as restrict outgoing traffic, providing granular control over the network access to your resources. The ability to define rules at the instance level allows for greater security and flexibility, as each instance can have its own specific set of permissions based on its role or function within your application architecture. This makes Security Groups a critical component of AWS’s security infrastructure. The other options relate to different AWS functionalities. The control of network access on a VPC level pertains to Network Access Control Lists (NACLs), which apply more broadly to subnets rather than to individual instances. Managing routing tables is a necessary aspect of networking within a VPC, but it does not involve controlling access or permissions. Automating scaling of resources generally relates to services like Auto Scaling Groups, which manage the number of instances based on load and demand rather than controlling traffic flow.