Question

Difficulty: MediumNetwork and Infrastructure Security

A gaming company is deploying matchmaking servers on Amazon EC2 instances within a Virtual Private Cloud (VPC). The network security architecture must meet the following requirements:
1. Control traffic at the individual instance level, ensuring that return traffic for allowed inbound requests is automatically permitted.
2. Control traffic at the subnet boundary, acting as a secondary layer of defense that requires explicit rules for both inbound and outbound traffic.

Which two AWS network security features should the company implement to meet these requirements? (Select TWO.)

  1. Security GroupsAnswer
  2. Network Access Control Lists (NACLs)Answer
  3. C
    AWS WAF
  4. D
    Amazon GuardDuty
  5. E
    AWS Shield

Answer

Security Groups and Network Access Control Lists (NACLs)
The correct choices are Security Groups and Network Access Control Lists (NACLs). Security Groups act as a firewall for EC2 instances and are stateful, meaning any allowed inbound traffic automatically permits the corresponding outbound return traffic. Network Access Control Lists (NACLs) act as a firewall at the subnet boundary and are stateless, meaning return traffic must be explicitly allowed by configuring both inbound and outbound rules.

Step-by-Step Solution

1
Identify the requirement for instance-level, stateful traffic control.
Security Groups are identified as the service that operates at the instance level and automatically permits return traffic due to their stateful nature.
This fulfills the first requirement of the scenario.
2
Identify the requirement for subnet-level, stateless traffic control.
Network Access Control Lists (NACLs) are identified as the service that operates at the subnet boundary and requires explicit rules for both inbound and outbound traffic because they are stateless.
This fulfills the second requirement of the scenario.

Key Concept

Understanding the differences between Security Groups (stateful, instance-level) and Network ACLs (stateless, subnet-level) in AWS VPC security.
Estimated Time:1m 30s
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