- A
The security group of the web server does not allow outbound traffic to the database.
Why wrong: Default security groups allow all outbound traffic; unless modified, this is unlikely.
- B
The network ACL of the web server subnet is blocking outbound traffic.
The outbound NACL on the web server subnet may block the connection request.
- C
The network ACL of the database subnet is blocking inbound traffic.
The inbound NACL on the database subnet may deny traffic, overriding the security group allow.
- D
The route table of the database subnet does not contain a route to the web server subnet.
Why wrong: VPC automatically adds a local route, so route tables are not an issue.
- E
The database server is not listening on the correct port.
Why wrong: This is an application-level issue, not a network connectivity issue.
Quick Answer
The answer is that the network ACL of the database subnet is blocking inbound traffic, and the network ACL of the web server’s subnet is blocking outbound traffic. This is because security groups are stateful and track connection state, automatically allowing return traffic, while network ACLs are stateless and require explicit rules for both inbound and outbound traffic at the subnet boundary. In this scenario, even if the database server’s security group permits the web server’s traffic, the stateless network ACL on the database subnet must have an inbound rule allowing the TCP SYN from the web server’s IP and port, and the web server’s subnet ACL must have an outbound rule permitting the SYN to leave. On the CompTIA Cloud+ CV0-004 exam, this tests your understanding of the fundamental difference between stateful security groups and stateless network ACLs, a common trap where candidates assume security group rules alone guarantee connectivity. Remember the mnemonic: “Security groups track state; ACLs need a mate”—meaning ACLs need both inbound and outbound rules to work together.
CV0-004 Operations and Support Practice Question
This CV0-004 practice question tests your understanding of operations and support. 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 a connectivity issue between a web server and a database server in the same VPC but different subnets. The security group for the database server allows inbound traffic from the web server's security group. However, the web server cannot establish a TCP connection to the database. What are two possible causes? (Choose two.)
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 network ACL of the web server subnet is blocking outbound traffic.
Option B is correct because network ACLs are stateless and apply to subnet boundaries. Even if the web server's security group allows outbound traffic, the subnet's network ACL must explicitly allow outbound traffic to the database server's IP and port. If the outbound rule is missing or denies the traffic, the TCP SYN packet will be dropped before it leaves the subnet. Option C is correct because the database subnet's network ACL must allow inbound traffic from the web server's IP and port; if it blocks the inbound SYN, the connection cannot be established.
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 security group of the web server does not allow outbound traffic to the database.
Why it's wrong here
Default security groups allow all outbound traffic; unless modified, this is unlikely.
- ✓
The network ACL of the web server subnet is blocking outbound traffic.
Why this is correct
The outbound NACL on the web server subnet may block the connection request.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
The network ACL of the database subnet is blocking inbound traffic.
Why this is correct
The inbound NACL on the database subnet may deny traffic, overriding the security group allow.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The route table of the database subnet does not contain a route to the web server subnet.
Why it's wrong here
VPC automatically adds a local route, so route tables are not an issue.
- ✗
The database server is not listening on the correct port.
Why it's wrong here
This is an application-level issue, not a network connectivity issue.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume security groups are the only firewall layer, forgetting that network ACLs at the subnet level can override security group rules, especially when they are stateless and require explicit rules for both directions.
Detailed technical explanation
How to think about this question
Network ACLs evaluate rules in numeric order and have separate inbound and outbound rule sets; they are stateless, meaning you must explicitly allow both inbound and outbound traffic for a bidirectional flow. Security groups, in contrast, are stateful and automatically allow return traffic for permitted outbound connections. In a multi-tier architecture, a common misconfiguration is forgetting to add an ephemeral port range (1024-65535) to the outbound ACL rule for the database subnet, which is required for the TCP SYN-ACK response to reach the web server.
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 security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.
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.
- →
Operations and Support — study guide chapter
Learn the concepts, then practise the questions
- →
Operations and Support practice questions
Targeted practice on this topic area only
- →
All CV0-004 questions
499 questions across all exam domains
- →
CompTIA Cloud+ CV0-004 study guide
Full concept coverage aligned to exam objectives
- →
CV0-004 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related CV0-004 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Operations and Support practice questions
Practise CV0-004 questions linked to Operations and Support.
Cloud Architecture and Design practice questions
Practise CV0-004 questions linked to Cloud Architecture and Design.
Security practice questions
Practise CV0-004 questions linked to Security.
Deployment practice questions
Practise CV0-004 questions linked to Deployment.
Troubleshooting practice questions
Practise CV0-004 questions linked to Troubleshooting.
CV0-004 fundamentals practice questions
Practise CV0-004 questions linked to CV0-004 fundamentals.
CV0-004 scenario practice questions
Practise CV0-004 questions linked to CV0-004 scenario.
CV0-004 troubleshooting practice questions
Practise CV0-004 questions linked to CV0-004 troubleshooting.
Practice this exam
Start a free CV0-004 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this CV0-004 question test?
Operations and Support — This question tests Operations and Support — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The network ACL of the web server subnet is blocking outbound traffic. — Option B is correct because network ACLs are stateless and apply to subnet boundaries. Even if the web server's security group allows outbound traffic, the subnet's network ACL must explicitly allow outbound traffic to the database server's IP and port. If the outbound rule is missing or denies the traffic, the TCP SYN packet will be dropped before it leaves the subnet. Option C is correct because the database subnet's network ACL must allow inbound traffic from the web server's IP and port; if it blocks the inbound SYN, the connection cannot be established.
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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Keep practising
More CV0-004 practice questions
- Match each cost management concept to its description.
- A load balancer log entry shows the above for a request. What is the MOST likely cause of the 504 error?
- Arrange the steps to deploy a new virtual machine in a public cloud environment (e.g., AWS, Azure, GCP) in the correct o…
- Sequence the steps to troubleshoot a cloud-based application that is not accessible from the internet.
- Order the steps to migrate an on-premises database to a cloud-managed database service (e.g., RDS, Cloud SQL).
- A company uses a hybrid cloud model with an on-premises data center and a public cloud. The network team reports that tr…
Last reviewed: Jun 25, 2026
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.