Google Professional Cloud Network Engineer Question 751
Select 4Google Cloud PlatformYour organization is experiencing connectivity issues between two Virtual Machine (VM) instances that are deployed in different subnets within the same VPC network. The instances cannot communicate, despite being in the same region and having the appropriate firewall rules in place. You suspect that there is an issue with routing or a firewall rule blocking the traffic. How can you determine the root cause of the issue using Google Cloud tools?
- A
Enable and analyze VPC Flow Logs for both VM instances to check the flow of traffic and identify any DENY logs.
- B
Use Packet Mirroring to capture and analyze network packets between the two VM instances to identify any anomalies.
- C
Review the firewall logs to verify if any specific firewall rule is blocking the traffic.
- D
Use Cloud NAT to resolve the issue by bypassing the firewall rules.
- E
Verify the route table for the VPC to ensure the subnets are correctly configured for communication.
Show answer and explanation
Correct answers: A, B, C, E
Explanation
To troubleshoot connectivity issues between VMs in the same VPC, you should use multiple tools to identify the root cause. VPC Flow Logs help analyze traffic flows and identify whether traffic is being allowed or denied. Packet Mirroring provides deeper insight into packet-level behavior. Firewall logs can confirm if a firewall rule is blocking the traffic. Additionally, verifying the route table ensures that traffic is being routed correctly between subnets. Cloud NAT is not relevant to this scenario because it addresses outbound internet access, not internal communication or firewall rules.
- A. Correct.
VPC Flow Logs can provide detailed information about the traffic flow between the instances, including whether the traffic is allowed or denied by firewall rules.
- B. Correct.
Packet Mirroring enables you to capture and analyze network traffic at the packet level, which can help identify issues such as malformed packets or unexpected traffic behavior.
- C. Correct.
Firewall logs can help you determine if any specific firewall rule is blocking the traffic between the two VM instances.
- D. Incorrect.
Cloud NAT is used to provide outbound internet access to VMs without external IPs, but it does not resolve internal communication issues or bypass firewall rules.
- E. Correct.
The route table determines how traffic is routed between subnets. Incorrect routing configurations can prevent communication between VMs in different subnets.