Default VPC and subnets in GCP - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Default VPC Subnet Regions

In Google Cloud Platform, the Default VPC is created automatically. How many subnets does the Default VPC have and where are they located?

A No subnets are created automatically; you must create them manually.

B One subnet only in the us-central1 region.

C Multiple subnets only in the us-east1 and europe-west1 regions.

D One subnet per region, covering all GCP regions by default.

💡 Hint

Think about how Google Cloud ensures network availability across regions by default.

The Default VPC includes one subnet in each GCP region, allowing resources in any region to communicate by default.

❓ service_behavior

intermediate

Behavior of Default VPC Firewall Rules

Which of the following statements correctly describes the default firewall rules applied to the Default VPC in GCP?

A Default firewall rules allow incoming SSH, RDP, and ICMP traffic from the internet.

B Default firewall rules allow all incoming traffic from any source to all instances.

C Default firewall rules block all incoming traffic by default.

D Default firewall rules allow incoming HTTP and HTTPS traffic from the internet.

💡 Hint

Consider the security posture of default firewall rules for internal and external traffic.

The Default VPC includes firewall rules that allow SSH (TCP port 22), RDP (TCP port 3389), and ICMP from the internet (0.0.0.0/0), in addition to all internal traffic within the VPC.

❓ Architecture

advanced

Impact of Deleting a Default VPC Subnet

What happens if you delete a subnet from the Default VPC in GCP?

A GCP prevents deletion of any Default VPC subnet to protect default resources.

B Only the deleted subnet is removed; other subnets and the VPC remain intact.

C The entire Default VPC is deleted automatically.

D All firewall rules associated with the Default VPC are deleted.

💡 Hint

Think about how GCP manages default resources and user modifications.

Deleting a subnet removes only that subnet. The Default VPC and other subnets remain. You can recreate subnets if needed.

❓ security

advanced

Security Risks of Using Default VPC

Which security risk is most associated with using the Default VPC without modification in a production environment?

A Default VPC firewall rules allow internal traffic but do not restrict outbound internet access, which may expose instances to external threats.

B Default VPC has no firewall rules, exposing all instances to the internet.

C Default VPC automatically encrypts all traffic, so there are no security risks.

D Default VPC disables logging, making it impossible to audit network activity.

💡 Hint

Consider what default firewall rules allow and what they do not restrict.

The Default VPC allows outbound internet access by default, which can expose instances to external threats if not properly secured.

✅ Best Practice

expert

Best Practice for Managing Default VPC in Large Organizations

In a large organization with multiple teams and projects, what is the best practice regarding the Default VPC and its subnets?

A Keep the Default VPC unchanged and rely on IAM roles to control access to resources.

B Use the Default VPC for all projects to simplify network management.

C Delete the Default VPC and create custom VPCs tailored to each team's needs with strict firewall rules.

D Merge all project networks into the Default VPC to reduce costs.

💡 Hint

Think about network isolation and security in multi-team environments.

Deleting the Default VPC and creating custom VPCs per team or project allows better isolation, security, and control over network policies.