Question 374 of 500

Quick Answer

The answer is a missing route on the database server’s routing table. Even when firewall rules are correct and the database service is active, the server may lack a return path to the application server’s subnet, causing packets to be dropped at Layer 3. This is a classic database migration connectivity issue cause: the destination can receive traffic but cannot reply because it has no route back to the source. On the CompTIA Project+ PK0-005 exam, this scenario tests your understanding of network troubleshooting beyond simple port checks—a common trap is assuming that open ports and a running service guarantee connectivity. Remember, routing is bidirectional; always verify that both the source and destination have routes to each other. A helpful memory tip is “two-way traffic, two-way routes”—if the database server cannot find its way home, the connection fails silently.

PK0-005 Practice Question: Basics of IT Infrastructure and IT Project Management

This PK0-005 practice question tests your understanding of basics of it infrastructure and it project management. 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.

During a database migration project, the team encounters an error when trying to connect to the new database server from the application server. The network team confirms that the ports are open and the firewall rules are correct. The database team reports that the database service is running and listening on the expected port. Which of the following is the MOST likely cause of the connectivity 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.

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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

Missing route on the database server's routing table

The most likely cause is a missing route on the database server's routing table. Even with correct firewall rules and an active database service, the database server may not have a return route to the application server's subnet, causing packets to be dropped. This is a common Layer 3 issue where the destination server can receive traffic but cannot reply because it lacks a route back to the source.

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.

  • Misconfigured DNS server

    Why it's wrong here

    A DNS issue would prevent name resolution, but connectivity errors typically involve IP addresses; the team likely used IP addresses directly or DNS would have been checked earlier.

  • Missing route on the database server's routing table

    Why this is correct

    Without a return route to the application server, the database server can receive packets but cannot send responses, resulting in a timeout or connection failure.

    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.

  • Incorrect subnet mask on the application server

    Why it's wrong here

    An incorrect subnet mask would likely cause local network issues, but the network team verified firewall rules and ports, suggesting the problem is beyond the application server's immediate network configuration.

  • Expired SSL certificate on the database server

    Why it's wrong here

    An expired SSL certificate would cause encryption handshake failures, not a basic TCP connectivity error.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates assume connectivity issues are always caused by firewalls or DNS, but CompTIA often tests the concept of asymmetric routing where the return path is missing, even when all outbound paths appear open.

Detailed technical explanation

How to think about this question

When a TCP connection is initiated, the client sends a SYN packet, the server responds with a SYN-ACK, and the client sends an ACK. If the database server lacks a route back to the application server's subnet, the SYN-ACK is never sent, causing the client to timeout. This can be verified using `traceroute` or `ping` from the database server to the application server, and checking the routing table with `ip route` (Linux) or `route print` (Windows). In real-world scenarios, this often occurs when a database server is moved to a new VLAN or cloud subnet without updating static routes or adding a default gateway.

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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.

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.

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FAQ

Questions learners often ask

What does this PK0-005 question test?

Basics of IT Infrastructure and IT Project Management — This question tests Basics of IT Infrastructure and IT Project Management — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Missing route on the database server's routing table — The most likely cause is a missing route on the database server's routing table. Even with correct firewall rules and an active database service, the database server may not have a return route to the application server's subnet, causing packets to be dropped. This is a common Layer 3 issue where the destination server can receive traffic but cannot reply because it lacks a route back to the source.

What should I do if I get this PK0-005 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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Last reviewed: Jun 30, 2026

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This PK0-005 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 PK0-005 exam.