VPC peering concept in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding VPC Peering Connectivity

Which statement correctly describes how two VPCs communicate when connected by a VPC peering connection?

A VPC peering allows direct routing of traffic between VPCs using private IP addresses without traversing the internet.

B Traffic between VPCs flows through the internet gateway of each VPC.

C VPC peering requires a VPN connection to enable communication between VPCs.

D VPC peering automatically shares all resources like security groups and route tables between VPCs.

💡 Hint

Think about how private networks connect without using the public internet.

VPC peering enables direct network routing between VPCs using private IPs, without using the internet or VPNs. It does not share resources automatically.

❓ Architecture

intermediate

VPC Peering Route Table Configuration

You have two VPCs peered: VPC-A (10.0.0.0/16) and VPC-B (10.1.0.0/16). To enable instances in VPC-A to reach instances in VPC-B, what must you do?

A Add a route in VPC-A's route table pointing 10.1.0.0/16 to the NAT gateway.

B Add a route in VPC-B's route table pointing 10.0.0.0/16 to the internet gateway.

C Add a route in VPC-A's route table pointing 10.1.0.0/16 to the VPC peering connection.

D No route changes are needed; peering automatically updates route tables.

💡 Hint

Think about how traffic knows where to go inside a network.

To route traffic to the peered VPC, you must add a route in the source VPC's route table pointing the destination CIDR to the peering connection.

❓ security

advanced

Security Group Behavior with VPC Peering

After establishing a VPC peering connection, which security group rule is required to allow inbound traffic from the peered VPC?

A No security group changes are needed because peering bypasses security groups.

B Allow inbound traffic only from the internet gateway IP in the security group.

C Allow inbound traffic from 0.0.0.0/0 in the security group of the receiving instance.

D Allow inbound traffic from the peered VPC's CIDR block in the security group of the receiving instance.

💡 Hint

Consider how security groups filter traffic based on IP ranges.

Security groups must explicitly allow inbound traffic from the IP range of the peered VPC to permit communication.

❓ service_behavior

advanced

Limitations of VPC Peering Connections

Which of the following is a true limitation of AWS VPC peering connections?

A VPC peering connections do not support transitive routing between peered VPCs.

B VPC peering connections allow automatic DNS resolution between VPCs without configuration.

C VPC peering connections can be created between any number of VPCs without limits.

D VPC peering connections automatically replicate security group rules across VPCs.

💡 Hint

Think about how traffic flows through multiple peered VPCs.

VPC peering does not support transitive routing; traffic cannot pass through one peered VPC to reach another.

✅ Best Practice

expert

Designing Scalable VPC Peering Architecture

You have 5 VPCs that need to communicate with each other. What is the best approach to minimize complexity and maintain security?

A Use internet gateways in each VPC and communicate over the public internet.

B Use a central VPC as a hub and peer all other VPCs to it (hub-and-spoke).

C Connect all VPCs through a VPN gateway in one VPC.

D Create peering connections between every pair of VPCs (full mesh).

💡 Hint

Consider how to reduce the number of connections while keeping control.

Hub-and-spoke reduces the number of peering connections and centralizes control, improving scalability and security.