The answer is that password changes are not replicating to the domain controller Samba authenticates against. This is the most likely cause because in an Active Directory environment, a password change is first written to the specific domain controller that processed the request from the Windows client. Samba, configured as a domain member using winbind and the idmap_ad backend, authenticates against a particular DC; if that DC has not yet received the replicated password update due to replication latency, authentication to Samba shares will fail. On the LPIC-2 exam, this scenario tests your understanding of AD replication mechanics versus local authentication, often appearing as a trap where candidates mistakenly blame winbind configuration or time skew. Remember the key insight: Samba does not see the password change until the DC it queries has the updated hash. Memory tip: “Password first, then propagate—Samba waits for the copy.”
LPIC-2 File Sharing and Samba Practice Question
This LPIC-2 practice question tests your understanding of file sharing and samba. 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.
A Samba server is configured as a domain member in an Active Directory environment. Users report that after changing their password on a Windows client, they cannot authenticate to Samba shares. The Samba server is using winbind and the 'idmap_ad' backend. 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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Password changes are not replicated to the domain controller that Samba authenticates against
In an Active Directory domain member configuration, Samba authenticates against a specific domain controller (DC). When a user changes their password on a Windows client, the new password is initially written to the DC that processed the change. If the Samba server's winbind service is authenticating against a different DC that has not yet received the replicated password update, authentication will fail. This is the most likely cause because password replication in AD is not instantaneous and depends on replication latency.
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 'winbind offline logon' option is not enabled
Why it's wrong here
Offline logon allows cached credentials, not related to password changes.
✓
Password changes are not replicated to the domain controller that Samba authenticates against
Why this is correct
If the DC contacted hasn't received the updated password, authentication fails.
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 winbind cache is outdated and needs to be cleared
Why it's wrong here
Clearing cache might help if there are stale entries, but the core issue is replication.
✗
The 'idmap backend' must be set to 'rid' instead of 'ad'
Why it's wrong here
Changing backend would require reconfiguration but not fix replication lag.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume the issue is with local caching or ID mapping backends, when in fact the root cause is the asynchronous replication of password changes between domain controllers in a multi-DC environment.
Detailed technical explanation
How to think about this question
Active Directory uses multi-master replication, meaning password changes are written to one DC and then replicated to others via the Knowledge Consistency Checker (KCC) and replication topology. The replication interval can be as short as 15 seconds within a site but may be longer across sites. Samba's winbind with 'idmap_ad' relies on the AD schema for ID mapping, but authentication still goes through Kerberos or NTLM to a specific DC; if that DC hasn't received the updated password hash, authentication fails with 'NT_STATUS_WRONG_PASSWORD'.
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 practitioner preparing for the LPIC-2 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.
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.
File Sharing and Samba — This question tests File Sharing and Samba — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Password changes are not replicated to the domain controller that Samba authenticates against — In an Active Directory domain member configuration, Samba authenticates against a specific domain controller (DC). When a user changes their password on a Windows client, the new password is initially written to the DC that processed the change. If the Samba server's winbind service is authenticating against a different DC that has not yet received the replicated password update, authentication will fail. This is the most likely cause because password replication in AD is not instantaneous and depends on replication latency.
What should I do if I get this LPIC-2 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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A Samba server is configured with 'security = ads' and joined to an Active Directory domain. Users can authenticate but cannot access shares. The smb.conf includes 'winbind use default domain = yes'. What could be the problem?
hard
A.The 'winbind use default domain' option should be 'no'
B.The 'idmap backend' is not configured
C.The Samba server's time is not synchronized with the domain controller
✓ D.The 'valid users' parameter uses domain prefix while default domain is set
Why D: When 'winbind use default domain = yes' is set, Winbind strips the domain prefix from usernames, so users authenticate as 'username' instead of 'DOMAIN\username'. If the 'valid users' parameter in a share definition explicitly uses the domain prefix (e.g., 'valid users = DOMAIN\username'), the stripped username will not match, and access is denied. This mismatch is the most direct cause of authentication succeeding but share access failing.
Last reviewed: Jun 11, 2026
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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.
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