This XK0-005 practice question tests your understanding of troubleshooting. 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
systemctl status sshd.service
● sshd.service - OpenSSH server daemon
Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
Active: active (running) since Mon 2025-03-10 10:30:25 UTC; 2h 15min ago
Main PID: 1234 (sshd)
CGroup: /system.slice/sshd.service
└─1234 /usr/sbin/sshd -D
journalctl -u sshd.service -p err --since "1 hour ago"
Mar 10 12:35:01 server sshd[5678]: error: Could not load host key: /etc/ssh/ssh_host_rsa_key
Mar 10 12:35:01 server sshd[5678]: error: Could not load host key: /etc/ssh/ssh_host_ecdsa_key
Mar 10 12:35:01 server sshd[5678]: fatal: No supported key exchange algorithms [preauth]
Refer to the exhibit. Users report they cannot SSH to the server. Based on the logs, 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.
systemctl status sshd.service
● sshd.service - OpenSSH server daemon
Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
Active: active (running) since Mon 2025-03-10 10:30:25 UTC; 2h 15min ago
Main PID: 1234 (sshd)
CGroup: /system.slice/sshd.service
└─1234 /usr/sbin/sshd -D
journalctl -u sshd.service -p err --since "1 hour ago"
Mar 10 12:35:01 server sshd[5678]: error: Could not load host key: /etc/ssh/ssh_host_rsa_key
Mar 10 12:35:01 server sshd[5678]: error: Could not load host key: /etc/ssh/ssh_host_ecdsa_key
Mar 10 12:35:01 server sshd[5678]: fatal: No supported key exchange algorithms [preauth]
A
Firewall is blocking port 22.
Why wrong: No firewall messages are shown; the error is about key exchange algorithms.
B
Host keys are missing or corrupted.
The error explicitly states 'Could not load host key' for multiple key files, leading to fatal error.
C
The SSH service is not running.
Why wrong: systemctl shows it is active (running).
D
SSH configuration has incorrect permissions.
Why wrong: The logs show missing keys, not permission issues.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Host keys are missing or corrupted.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Firewall is blocking port 22.
Why it's wrong here
No firewall messages are shown; the error is about key exchange algorithms.
✓
Host keys are missing or corrupted.
Why this is correct
The error explicitly states 'Could not load host key' for multiple key files, leading to fatal error.
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 SSH service is not running.
Why it's wrong here
systemctl shows it is active (running).
✗
SSH configuration has incorrect permissions.
Why it's wrong here
The logs show missing keys, not permission issues.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Trap categories for this question
Command / output trap
No firewall messages are shown; the error is about key exchange algorithms.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 XK0-005 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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this XK0-005 question in full detail.
Identify which XK0-005 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Troubleshooting — This question tests Troubleshooting — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Host keys are missing or corrupted.
What should I do if I get this XK0-005 question wrong?
Identify which XK0-005 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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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