Default VPC overview in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the main purpose of a Default VPC in AWS?

Imagine you just created a new AWS account. AWS automatically creates a Default VPC for you. What is the main purpose of this Default VPC?

A It automatically creates private subnets only, so instances cannot access the internet.

B It restricts all network traffic by default to increase security.

C It provides a ready-to-use network environment so you can launch instances without configuring networking.

D It is a backup network that activates only if you delete your custom VPCs.

💡 Hint

Think about what happens when you launch an instance without creating any network settings.

The Default VPC is designed to let users launch instances immediately with internet access and basic networking without extra setup.

❓ Architecture

intermediate

Which components are included by default in an AWS Default VPC?

When AWS creates a Default VPC in your account, which of the following components does it include by default?

A Only private subnets with no internet gateway attached.

B No subnets, only a virtual private gateway.

C Multiple NAT gateways and no internet gateway.

D One public subnet in each Availability Zone, an internet gateway, and default route tables.

💡 Hint

Think about how instances in the Default VPC can access the internet.

The Default VPC includes one public subnet per AZ, an internet gateway attached, and route tables that send internet traffic through the gateway.

❓ security

advanced

What is the default security group behavior in a Default VPC?

Consider the default security group created with the Default VPC. What is its default behavior regarding inbound and outbound traffic?

A Allows all outbound traffic and inbound traffic only from instances assigned to the same security group.

B Allows all inbound and outbound traffic from any source.

C Blocks all inbound and outbound traffic by default.

D Allows inbound traffic from the internet but blocks all outbound traffic.

💡 Hint

Think about how instances in the same security group communicate by default.

The default security group allows all outbound traffic and inbound traffic only from instances assigned to the same group, providing basic isolation.

❓ service_behavior

advanced

What happens if you delete the Default VPC in your AWS account?

After deleting the Default VPC, what is the behavior of AWS regarding Default VPCs in your account?

A AWS does not recreate it automatically; you must create a new VPC manually.

B AWS automatically recreates the Default VPC after 24 hours.

C AWS creates a Default VPC only when you launch your first instance after deletion.

D AWS disables your account until you create a new Default VPC.

💡 Hint

Think about whether AWS automatically restores deleted resources.

Once deleted, the Default VPC is not recreated automatically. You must create your own VPC or use the VPC wizard.

✅ Best Practice

expert

Which is the best practice regarding the use of Default VPCs in production environments?

For a secure and scalable production environment, what is the recommended approach to using Default VPCs?

A Use the Default VPC as is, since it is preconfigured for internet access and easy setup.

B Delete the Default VPC and create custom VPCs with tailored subnetting, routing, and security controls.

C Use multiple Default VPCs across regions to increase redundancy.

D Keep the Default VPC but disable the internet gateway to prevent internet access.

💡 Hint

Think about control and security needs in production.

Production environments benefit from custom VPCs designed for specific security, subnet, and routing needs rather than relying on the Default VPC.