Google Professional Cloud Network Engineer Question 218
Single answerGoogle Cloud PlatformYou are responsible for networking at your company and have set up VPC Network Peering between two VPCs: 'VPC-A' and 'VPC-B'. After the peering was successfully established, you notice that some services hosted in VPC-B are still inaccessible from VPC-A. What could be the reason for this issue?
- A
Firewall rules are not configured to allow traffic between VPC-A and VPC-B.
- B
VPC Network Peering does not support internal DNS resolution between peered VPCs.
- C
The subnets in VPC-A and VPC-B have overlapping IP address ranges.
- D
Routes were not automatically created in VPC-A to reach the subnets in VPC-B.
Show answer and explanation
Correct answer: A
Explanation
When VPC Network Peering is established, routes are automatically created to enable connectivity between the subnets of the peered VPCs. However, by default, no traffic is allowed unless explicitly permitted by firewall rules. Therefore, the lack of appropriate firewall rules is the most likely cause of the issue in this scenario.
- A. Correct.
Firewall rules are required to allow traffic between peered VPCs. Even though VPC Network Peering handles the connectivity, firewall rules must be explicitly configured to allow traffic.
- B. Incorrect.
This is incorrect because VPC Network Peering supports internal DNS resolution, provided it is enabled for the peering connection.
- C. Incorrect.
Overlapping IP address ranges prevent the establishment of VPC Network Peering itself. However, in this scenario, the peering was already established.
- D. Incorrect.
VPC Network Peering automatically creates routes between the peered VPCs to allow communication. Manual route creation is not required.