AWS Certified Solutions Architect – Professional — Question 501

Which of the following are characteristics of Amazon VPC subnets? (Choose two.)

Answer options

• A. Each subnet spans at least 2 Availability Zones to provide a high-availability environment.
• B. Each subnet maps to a single Availability Zone.
• C. CIDR block mask of /25 is the smallest range supported.
• D. By default, all subnets can route between each other, whether they are private or public.
• E. Instances in a private subnet can communicate with the Internet only if they have an Elastic IP.

Correct answer: B, D

Explanation

In Amazon VPC, every subnet is uniquely mapped to a single Availability Zone and cannot span across multiple zones. Additionally, the default local route in the VPC route table enables all subnets within that VPC to communicate with each other by default. Other options are incorrect because the smallest supported subnet size is /28, and private subnets require a NAT gateway rather than just an Elastic IP to access the Internet.