The answer is that the user is entering the wrong password. The journalctl output shows a clear sequence of 'Failed password for user' followed by 'Connection closed by authenticating user', which is the exact log pattern generated by the SSH daemon (sshd) when a password authentication attempt fails and the session is terminated. On the CompTIA Linux+ XK0-005 exam, this scenario tests your ability to interpret SSH authentication failure logs from journalctl, a key skill for diagnosing remote access issues. A common trap is confusing this with key-based authentication failures or firewall blocks, but the absence of 'Connection refused' or 'Permission denied (publickey)' messages confirms the issue is purely a password mismatch. Memory tip: think of the three-word chain—'Failed password' always points to a typing error, not a system block.
XK0-005 Troubleshooting Practice Question
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
Refer to the exhibit.
-- Logs begin at Tue 2023-06-01 08:15:32 EDT, end at Tue 2023-06-01 09:23:11 EDT. --
Jun 01 08:20:01 server sshd[1234]: Connection from 192.168.1.100 port 22
Jun 01 08:20:05 server sshd[1234]: Failed password for root from 192.168.1.100 port 22 ssh2
Jun 01 08:20:10 server sshd[1234]: Connection closed by authenticating user root 192.168.1.100 port 22 [preauth]
Refer to the exhibit. A remote user is unable to SSH to the server. Based on the journalctl output, 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.
Refer to the exhibit.
-- Logs begin at Tue 2023-06-01 08:15:32 EDT, end at Tue 2023-06-01 09:23:11 EDT. --
Jun 01 08:20:01 server sshd[1234]: Connection from 192.168.1.100 port 22
Jun 01 08:20:05 server sshd[1234]: Failed password for root from 192.168.1.100 port 22 ssh2
Jun 01 08:20:10 server sshd[1234]: Connection closed by authenticating user root 192.168.1.100 port 22 [preauth]
A
The user is entering the wrong password
Failed password attempt is logged.
B
The SSH service is not running
Why wrong: The log shows connections are being processed.
C
The user's IP address is in the hosts.deny file
Why wrong: Would show a different log message, like 'Connection refused'.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The user is entering the wrong password
The journalctl output shows 'Failed password for user' followed by 'Connection closed by authenticating user', which indicates that the SSH authentication process was attempted but failed due to an incorrect password. This log entry is generated by the SSH daemon (sshd) when a password authentication attempt fails, and the connection is subsequently closed. No other errors (e.g., connection refused, timeout, or denied by hosts.deny) are present, making incorrect password the most likely cause.
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 user is entering the wrong password
Why this is correct
Failed password attempt is logged.
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
The log shows connections are being processed.
✗
The user's IP address is in the hosts.deny file
Why it's wrong here
Would show a different log message, like 'Connection refused'.
✗
The SSH port is blocked by a firewall
Why it's wrong here
Connections are reaching the server.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CompTIA often tests the distinction between authentication failures (password/keys) and connectivity failures (service down, firewall, hosts.deny) — the trap here is that candidates see 'Connection closed' and assume a firewall or hosts.deny block, but the 'Failed password' line clearly pinpoints the authentication phase.
Trap categories for this question
Command / output trap
The log shows connections are being processed.
Detailed technical explanation
How to think about this question
SSH password authentication uses the PAM (Pluggable Authentication Modules) stack; when a password fails, sshd logs the attempt and increments the failed count, which can trigger rate-limiting or account lockout via pam_tally2 or fail2ban. The 'Connection closed by authenticating user' message specifically indicates that the client disconnected after the authentication failure, often due to reaching MaxAuthTries (default 6) or the client giving up. In real-world scenarios, this log pattern is commonly seen with brute-force attacks or users mistyping passwords, and administrators should check /var/log/secure or auth.log for additional context.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this XK0-005 question in full detail.
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: The user is entering the wrong password — The journalctl output shows 'Failed password for user' followed by 'Connection closed by authenticating user', which indicates that the SSH authentication process was attempted but failed due to an incorrect password. This log entry is generated by the SSH daemon (sshd) when a password authentication attempt fails, and the connection is subsequently closed. No other errors (e.g., connection refused, timeout, or denied by hosts.deny) are present, making incorrect password the most likely cause.
What should I do if I get this XK0-005 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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