Scenario: A user receives “authentication failure” on login. Question: What should you check first?

Question

BlackTom AI · Accepted Answer

Authentication failures most commonly come from invalid credentials or account state (expired password, locked/disabled account), so start by checking the user’s password expiry and account status.

1) Relevant knowledge points and concepts
- Authentication failure messages usually indicate credential or account-state problems (expired password, locked account, disabled shell) rather than resource metrics.
- System account state is visible in /etc/shadow, passwd/chage output and authentication logs (/var/log/auth.log, /var/log/secure).
- Tools: passwd -S, chage -l, sudo faillock or pam_tally2; check /etc/shadow for “!” or “*” marking locked accounts.

2) Step-by-step reasoning process
- Ask the user to retype the password to rule out simple typing error.
- On the host, run: passwd -S username (shows password status) and chage -l username (shows expiry dates).
- Inspect /etc/shadow: a leading “!” or “*” in the password field indicates a locked account; a date field indicates expiry.
- Check authentication logs: sudo tail -n 50 /var/log/auth.log (Debian/Ubuntu) or /var/log/secure (RHEL/CentOS) for messages like “Account expired”, “Authentication failure”, or “Account locked”.
- If locked or expired, unlock/reset password or extend expiry per policy.

3) Commands / intermediate checks (examples)
- passwd -S alice
- chage -l alice
- sudo tail -n 100 /var/log/auth.log | grep alice
- sudo faillock --user alice (or pam_tally2 --user alice)

4) Why the correct answer is correct
Password expiry or locked/disabled account directly produce “authentication failure” at login. These are the most immediate and common causes to verify before escalating.

5) Why other options are incorrect
- a. Disk space: low disk can break logins indirectly but would more commonly cause different errors (e.g., unable to write log), not immediate authentication failure.
- b. CPU usage: high CPU may slow the system but does not specifically cause authentication to fail.
- c. File permissions: incorrect permissions on auth files could break auth system, but this is less common and not the first thing to check for a single user’s authentication failure.

Conclusion: The correct first check is the user’s password expiry and account status (d), which matches the provided answer.

Scenario: A user receives “authentication failure” on login. Question: What should you check first?单项选择题

类似问题

Which security measure will stop someone reading your messages if they find your smart phone?

Question 44

Scenario: A user receives “authentication failure” on login. Question: What should you check first?

Scenario: A user receives “authentication failure” on login. Question: What should you check first?

What is a method for confirming users’ identities?

Which of the following trees corresponds to a potential parse of the ambiguous sentence below, with correct syntactic categories? Some diagnostics are provided.

Which of the following sentences contain two non-finite verbs? Select all that apply.

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单