The answer is a host-based firewall rule blocking the specific application port on the user’s VM. This is correct because the user can access other applications in the same subnet, proving that general network connectivity and subnet routing are intact; the issue is isolated to a single application, which points directly to a host firewall filtering traffic by port or protocol. On the CompTIA Cloud+ CV0-004 exam, this scenario tests your ability to distinguish between network-level and host-level security controls, a common trap where candidates mistakenly blame subnet ACLs or routing when the symptom is application-specific. Remember the memory tip: “One app down, others fine? Check the host firewall line.” This helps you zero in on host-based rules rather than broader network policies when troubleshooting host firewall blocking application access.
CV0-004 Security Practice Question
This CV0-004 practice question tests your understanding of security. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A cloud administrator is troubleshooting an issue where a user in the finance department cannot access a critical application hosted on a private cloud. The user can access other applications in the same subnet. The security team recently implemented a new network security policy. Which of the following is MOST likely causing the issue?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A host-based firewall rule is blocking the specific application port on the user's VM.
Option D is correct because the user can access other applications in the same subnet, indicating network connectivity is intact, but a specific application is blocked. A host-based firewall rule on the user's VM (e.g., Windows Firewall or iptables) can filter traffic by port or protocol, and a newly implemented security policy likely added a rule blocking the port used by the critical application. This explains why only that application is inaccessible while others work.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 user's VM is isolated from the subnet due to a misconfigured VLAN.
Why it's wrong here
The user can access other applications in the same subnet, so VLAN misconfiguration is unlikely.
✗
The user's account has been disabled due to a failed login attempt.
Why it's wrong here
The user can still access other applications, so the account is active.
✗
The hypervisor is denying access to the application due to a resource quota violation.
Why it's wrong here
Resource quota violations would affect all applications or VMs, not just one application.
✓
A host-based firewall rule is blocking the specific application port on the user's VM.
Why this is correct
A host-based firewall rule could block only the specific port used by the application, which explains why other applications work.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume network-level issues (like VLAN misconfiguration) or account problems, but the key clue is that other applications in the same subnet are accessible, pointing to a host-based filter rather than a network-wide or authentication issue.
Detailed technical explanation
How to think about this question
Host-based firewalls operate at OSI Layer 4 (transport layer) using port numbers and protocols (TCP/UDP). For example, a Windows Firewall rule can block inbound TCP port 443 for a specific application while allowing port 80. The security team's new policy likely added an ACL or firewall rule targeting the application's port, which can be verified with commands like `netsh advfirewall firewall show rule name=all` on Windows or `iptables -L -n -v` on Linux. In real-world scenarios, such rules are often deployed via Group Policy or security baselines, causing subtle access issues that are hard to trace without checking local firewall logs.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Security — This question tests Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: A host-based firewall rule is blocking the specific application port on the user's VM. — Option D is correct because the user can access other applications in the same subnet, indicating network connectivity is intact, but a specific application is blocked. A host-based firewall rule on the user's VM (e.g., Windows Firewall or iptables) can filter traffic by port or protocol, and a newly implemented security policy likely added a rule blocking the port used by the critical application. This explains why only that application is inaccessible while others work.
What should I do if I get this CV0-004 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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