VPC peering in GCP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Architecture

intermediate

Understanding VPC Peering Connectivity

You have two VPC networks in Google Cloud: VPC-A and VPC-B. You create a VPC peering connection between them. Which statement best describes the connectivity after peering?

A Instances in VPC-A can communicate with instances in VPC-B using internal IPs without additional routes.

B Instances in VPC-A can communicate with instances in VPC-B only if you create custom routes manually.

C VPC peering allows communication only over public IP addresses between VPC-A and VPC-B.

D VPC peering automatically merges both VPCs into a single network with shared IP ranges.

💡 Hint

Think about how VPC peering connects networks internally.

VPC peering allows instances in peered VPCs to communicate using internal IP addresses without needing manual route creation. It does not merge networks or require public IPs.

❓ security

intermediate

Firewall Rules and VPC Peering

You have two peered VPCs in Google Cloud. You want to allow traffic from VPC-A to VPC-B instances on port 8080. What must you do to allow this traffic?

A Create a firewall rule in VPC-A allowing egress on port 8080 to VPC-B's IP range.

B Create a firewall rule in VPC-B allowing ingress on port 8080 from VPC-A's IP range.

C No firewall rules are needed because VPC peering automatically allows all traffic.

D Create firewall rules in both VPC-A and VPC-B allowing traffic on port 8080.

💡 Hint

Remember which side controls incoming traffic.

Firewall rules are stateful and applied per VPC. To allow traffic to VPC-B instances, you must create an ingress rule in VPC-B allowing traffic from VPC-A's IP range on the desired port.

❓ service_behavior

advanced

Routing Behavior in VPC Peering

You have three VPCs: VPC-A, VPC-B, and VPC-C. VPC-A is peered with VPC-B, and VPC-B is peered with VPC-C. Can instances in VPC-A communicate directly with instances in VPC-C through VPC-B?

A Yes, VPC peering supports transitive routing, so VPC-A can reach VPC-C through VPC-B.

B Yes, but only if you configure custom routes in VPC-B to forward traffic.

C No, VPC peering does not support transitive routing; VPC-A cannot reach VPC-C through VPC-B.

D No, VPC peering disables all routing between peered networks.

💡 Hint

Think about whether VPC peering allows traffic to pass through a third VPC.

VPC peering does not support transitive routing. Traffic cannot pass through a peered VPC to reach another peered VPC. Each peering connection is isolated.

❓ Configuration

advanced

VPC Peering IP Range Overlap

You try to create a VPC peering connection between two VPCs, but the request fails. Both VPCs have overlapping IP ranges. What is the reason?

A VPC peering requires non-overlapping IP address ranges between peered VPCs.

B VPC peering requires both VPCs to be in the same region.

C VPC peering requires both VPCs to use the same IP range.

D VPC peering only works if one VPC uses public IPs and the other uses private IPs.

💡 Hint

Consider IP address conflicts in network connections.

VPC peering connections require that the IP address ranges of the two VPCs do not overlap to avoid routing conflicts.

✅ Best Practice

expert

Managing VPC Peering at Scale

You manage 10 VPCs in Google Cloud and want to enable communication between all of them. What is the best approach to connect all VPCs efficiently?

A Use transitive peering by chaining peering connections through one VPC.

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

C Assign the same IP range to all VPCs to simplify routing.

D Use a hub-and-spoke model with a shared VPC as the hub and peer all VPCs to it.

💡 Hint

Think about scalability and manageability of network connections.

Full mesh peering grows exponentially and is hard to manage. Transitive peering is not supported. Using a shared VPC as a hub and peering other VPCs to it simplifies management and scales better.