LPIC-2 System Security Practice Question
A security analyst notices that an /etc/pam.d/common-auth file contains the line 'auth required pam_tally2.so deny=5'. What is the effect?
⚠ Common exam trap
Watch out — candidates often confuse `pam_tally2.so` with `pam_unix.so` or `pam_cracklib.so` for password aging, or mistakenly think `deny=5` limits concurrent sessions rather than failed login attempts.
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
✓
Account lockout after 5 failed login attempts
The `pam_tally2.so` module tracks login attempts and, when used with `deny=5`, locks the account after five consecutive failed authentication attempts. The `required` control ensures that if the tally threshold is exceeded, authentication fails immediately, preventing further access until the count is reset by an administrator or via `pam_tally2` reset.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Log failed attempts only
Why it's wrong here
pam_tally2.so logs but also can lock; deny triggers lockout.
- ✗
Password expiration after 5 days
Why it's wrong here
Password expiration is handled by pam_unix.so with expiration settings.
- ✗
Maximum 5 concurrent sessions
Why it's wrong here
Concurrent session limits are set by pam_limits.so.
- ✓
Account lockout after 5 failed login attempts
Why this is correct
pam_tally2.so with deny=5 locks the account after 5 failed login attempts.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LPIC-2 practice question is part of Courseiva's free LPI 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 LPIC-2 exam.