CompTIA
CV0-003 · Question #152
CV0-003 Question #152: Real Exam Question with Answer & Explanation
The correct answer is D: Incorrect firewall configuration. Two VMs sharing the same /24 subnet can still fail to communicate if a firewall or security policy is blocking traffic between them at the host or network level.
Troubleshooting
Question
Two VMs are in the same subnet 10.120.10.x/24, but the VMs cannot communicate with each other. Which of the following could be causing this problem?
Options
- APrivate IP addresses are not routable
- BIncorrect VLAN tagging
- CIncorrect subnetting
- DIncorrect firewall configuration
Explanation
Two VMs sharing the same /24 subnet can still fail to communicate if a firewall or security policy is blocking traffic between them at the host or network level.
Common mistakes.
- A. Private RFC 1918 IP addresses are fully routable within a local network and are the standard addressing scheme used for VMs on the same subnet - they do not prevent communication.
- B. VLAN tagging issues would prevent layer 2 reachability entirely, but the question already confirms both VMs share the same subnet, making this an unlikely cause for intra-segment communication failure.
- C. Both VMs are explicitly stated to reside in the same 10.120.10.x/24 subnet, ruling out incorrect subnetting as the cause.
Concept tested. Intra-subnet VM traffic blocked by firewall policy
Reference. https://learn.microsoft.com/en-us/azure/virtual-network/network-security-groups-overview
Topics
#VLAN tagging#VM communication#firewall rules#network troubleshooting
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