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.
Exhibit
Refer to the exhibit.
[2025-02-20 14:32:15] ERROR: Connection timeout to database endpoint db.example.com:3306
[2025-02-20 14:32:20] WARN: Retry attempt 1 of 3...
[2025-02-20 14:32:25] ERROR: All retries exhausted. Falling back to cached data.
A cloud application is intermittently slow. Based on the exhibit, which of the following is the most likely cause?
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.
Refer to the exhibit.
[2025-02-20 14:32:15] ERROR: Connection timeout to database endpoint db.example.com:3306
[2025-02-20 14:32:20] WARN: Retry attempt 1 of 3...
[2025-02-20 14:32:25] ERROR: All retries exhausted. Falling back to cached data.
A
A network security group is blocking port 3306.
Blocking the port prevents TCP handshake, causing a timeout. This matches the error logs.
B
The database server is overloaded.
Why wrong: Overloaded database would likely produce slow query responses or error messages, not consistent connection timeouts.
C
The database endpoint DNS record is incorrect.
Why wrong: An incorrect DNS record would cause a name resolution failure (e.g., 'Name or service not known'), not a timeout.
D
The application has insufficient memory.
Why wrong: Insufficient memory would lead to out-of-memory errors or swapping, not database connection timeouts.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A network security group is blocking port 3306.
The intermittent slowness points to a network security group blocking port 3306, which is used by MySQL/MariaDB. When the NSG intermittently drops packets to this port, the application experiences timeouts and retries, causing sporadic slowdowns. This is a common issue in cloud environments where security rules are misconfigured or applied at the wrong priority level.
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.
✓
A network security group is blocking port 3306.
Why this is correct
Blocking the port prevents TCP handshake, causing a timeout. This matches the error logs.
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.
✗
The database server is overloaded.
Why it's wrong here
Overloaded database would likely produce slow query responses or error messages, not consistent connection timeouts.
✗
The database endpoint DNS record is incorrect.
Why it's wrong here
An incorrect DNS record would cause a name resolution failure (e.g., 'Name or service not known'), not a timeout.
✗
The application has insufficient memory.
Why it's wrong here
Insufficient memory would lead to out-of-memory errors or swapping, not database connection timeouts.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CompTIA often tests the distinction between intermittent failures (caused by network filtering or transient connectivity issues) versus persistent failures (caused by overload or misconfiguration), leading candidates to incorrectly choose database overload or DNS errors.
Detailed technical explanation
How to think about this question
Port 3306 is the default MySQL port; network security groups (NSGs) in cloud platforms like Azure or AWS act as stateful firewalls. Intermittent blocking can occur due to overlapping rules, misordered priorities, or when a rule is applied to a subnet but not propagated instantly. The application's retry logic (e.g., exponential backoff) can amplify the perceived slowness as each failed connection attempt adds latency.
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 practitioner preparing for the CV0-004 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
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 — 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: A network security group is blocking port 3306. — The intermittent slowness points to a network security group blocking port 3306, which is used by MySQL/MariaDB. When the NSG intermittently drops packets to this port, the application experiences timeouts and retries, causing sporadic slowdowns. This is a common issue in cloud environments where security rules are misconfigured or applied at the wrong priority level.
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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