Google Professional Cloud Network Engineer Question 740
Select 3Google Cloud PlatformYour company has set up a site-to-site VPN between your on-premises environment and Google Cloud using Cloud VPN. The VPN connection was working fine, but recently, some on-premises servers are unable to communicate with resources in Google Cloud. After reviewing the Cloud VPN logs, you notice that the VPN tunnel is in an 'Established' state. What should you do to troubleshoot and resolve the issue?
- A
Verify that the on-premises firewall rules allow the required traffic to and from Google Cloud.
- B
Check that the Cloud Router is advertising the correct subnets to the on-premises environment.
- C
Recreate the VPN tunnel to resolve potential configuration issues.
- D
Verify that the VPC firewall rules in Google Cloud allow traffic for the affected resources.
- E
Inspect the MTU settings on both the on-premises and Google Cloud networks.
Show answer and explanation
Correct answers: A, B, D
Explanation
In this scenario, the VPN tunnel is in an 'Established' state, which means the VPN connection itself is functioning. The issue is likely related to routing or firewall configurations. Verifying on-premises and VPC firewall rules ensures that traffic is not being blocked. Additionally, ensuring that Cloud Router is advertising the correct subnets is critical for proper routing between on-premises and Google Cloud. Recreating the VPN tunnel or inspecting MTU settings are unnecessary here since the issue is more likely tied to configuration rather than the tunnel itself.
- A. Correct.
Correct: If the on-premises firewall rules do not allow traffic between the affected servers and Google Cloud, the communication will fail even if the VPN tunnel is established.
- B. Correct.
Correct: Cloud Router is responsible for dynamic route advertisement. If the wrong subnets are being advertised, the on-premises environment may not know how to reach certain Google Cloud subnets, causing communication issues.
- C. Incorrect.
Incorrect: Recreating the VPN tunnel is unnecessary in this scenario because the VPN tunnel is in an 'Established' state, indicating that the tunnel itself is functioning properly.
- D. Correct.
Correct: VPC firewall rules in Google Cloud control traffic to and from resources. If these rules are misconfigured, communication between on-premises and Google Cloud resources can fail.
- E. Incorrect.
Incorrect: While MTU settings can sometimes cause connectivity issues, the problem described in this scenario is more likely related to routing or firewall rules based on the details provided.