hardMultiple ChoiceObjective-mapped
CV0-004 Practice Question: Is troubleshooting an issue where a virtual…
A cloud engineer is troubleshooting an issue where a virtual machine (VM) in a VPC cannot communicate with an on-premises database server through a site-to-site VPN. The VPN tunnel status shows 'UP' and the on-premises firewall logs show packets from the VM's public IP (but the VM is in a private subnet with no public IP). What is the MOST likely cause?
⚠ Common exam trap
The trap here is that candidates see 'VPN tunnel UP' and assume the VPN is fully functional, overlooking that routing (the route table) is a separate layer that must direct traffic into the tunnel; the tunnel being up does not guarantee traffic is being sent through it.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The route table for the subnet is missing a route to the on-premises network via the VPN.
The VPN tunnel status is 'UP' and the on-premises firewall sees packets from the VM's public IP, but the VM is in a private subnet with no public IP. This indicates that the VM's traffic is being sent to the internet instead of through the VPN tunnel. The most likely cause is that the subnet's route table lacks a specific route directing traffic destined for the on-premises network to the virtual private gateway (VGW) or VPN connection, causing the traffic to be routed to the internet gateway (IGW) and source-NATed to the public IP.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The on-premises firewall is blocking the VM's private IP address.
Why it's wrong here
Firewall logs show packets from public IP, indicating traffic is not arriving via VPN tunnel.
- ✗
The VM's security group is blocking outbound traffic to the on-premises subnet.
Why it's wrong here
Security groups would drop traffic entirely, not cause it to appear from a public IP.
- ✓
The route table for the subnet is missing a route to the on-premises network via the VPN.
Why this is correct
Without proper route, traffic may exit through an internet gateway or NAT, resulting in public IP source.
- ✗
The VPN tunnel is misconfigured with mismatched pre-shared keys.
Why it's wrong here
Mismatched keys would prevent the tunnel from establishing; tunnel status is UP.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CV0-004 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CV0-004 exam.