The answer is a mismatched MTU size across the VPN tunnel. This is the most likely cause because when the VPN connection is up but traffic suffers from high latency and packet loss, the issue is often that packets exceeding the tunnel’s Maximum Transmission Unit must be fragmented; if the Don’t Fragment (DF) bit is set, those packets are silently dropped, forcing retransmissions and degrading performance. On the CompTIA Cloud+ CV0-004 exam, this scenario tests your ability to differentiate between a functional tunnel and a performance bottleneck—a common trap is assuming the problem is bandwidth throttling or routing, when the real culprit is MTU mismatch. Remember that a “live” VPN does not guarantee optimal throughput; always check packet size when latency spikes. Memory tip: think “MTU = Must Tune Up” for hybrid cloud VPNs.
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 company uses a hybrid cloud model with an on-premises data center and a public cloud. The network team reports that traffic between the cloud and on-premises is experiencing high latency and packet loss. The cloud administrator verifies that the VPN connection is up. What 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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The VPN tunnel has a mismatched MTU size.
When a VPN tunnel is up but traffic experiences high latency and packet loss, a mismatched Maximum Transmission Unit (MTU) size is a common cause. This occurs because packets larger than the tunnel's MTU must be fragmented, and if fragmentation is not properly handled (e.g., due to the DF bit being set), packets are dropped, leading to retransmissions and increased latency. The symptoms align with MTU issues rather than simple connectivity or throttling problems.
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 firewall rule is blocking ICMP packets.
Why it's wrong here
Blocking ICMP would not cause high latency; connection would drop.
✗
VMs are placed in different cloud regions.
Why it's wrong here
Region placement affects latency but not packet loss on VPN.
✓
The VPN tunnel has a mismatched MTU size.
Why this is correct
Mismatched MTU causes fragmentation and packet loss.
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 cloud provider is throttling bandwidth.
Why it's wrong here
Throttling reduces throughput but not packet loss.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume a 'VPN is up' means all traffic flows perfectly, but CompTIA often tests the subtlety that MTU mismatch causes performance degradation without breaking the tunnel itself, leading them to incorrectly blame firewall rules or bandwidth throttling.
Detailed technical explanation
How to think about this question
MTU mismatch in VPN tunnels often involves the overhead from encapsulation protocols like IPsec (adding 50-60 bytes) or GRE (24 bytes). The standard Ethernet MTU is 1500 bytes, but after encapsulation, the effective MTU becomes smaller (e.g., 1438 bytes for IPsec). If the on-premises router or cloud gateway does not adjust the MTU or enable Path MTU Discovery (PMTUD) with ICMP unreachable messages, packets exceeding the tunnel MTU are silently dropped. This is a classic issue in hybrid cloud setups where the VPN tunnel traverses multiple network segments.
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: The VPN tunnel has a mismatched MTU size. — When a VPN tunnel is up but traffic experiences high latency and packet loss, a mismatched Maximum Transmission Unit (MTU) size is a common cause. This occurs because packets larger than the tunnel's MTU must be fragmented, and if fragmentation is not properly handled (e.g., due to the DF bit being set), packets are dropped, leading to retransmissions and increased latency. The symptoms align with MTU issues rather than simple connectivity or throttling problems.
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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