LPIC-2 File Sharing and Samba Practice Question
A company runs a mixed Linux/Windows environment. The Samba server (version 4.15) is configured as a domain member using 'security = ADS'. Recently, the IT team enabled 'winbind use default domain = yes' to simplify logins. After the change, users report that they can no longer access Samba shares when authenticating with just their username (e.g., 'jdoe') instead of 'DOMAIN\jdoe'. However, authentication using the full domain-qualified name still works. The smb.conf includes:
[global]
security = ADS workgroup = MYDOM realm = MYDOM.LOCAL winbind use default domain = yes winbind separator = /
Users are in the 'Domain Users' group and the share configuration is:
[share]
path = /srv/share valid users = @"MYDOM\domain users"
Which of the following is the most likely cause and solution?
⚠ Common exam trap
Test-takers frequently assume the forward slash separator is interchangeable with backslash in Samba, but in the context of 'winbind use default domain = yes', only backslash works correctly for default domain username resolution.
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
✓
Change 'winbind separator' to backslash or remove it to default to backslash
When 'winbind use default domain = yes' is set, Samba expects the winbind separator to be a backslash (\), not a forward slash (/). With a forward slash separator, the username 'jdoe' is not correctly mapped to 'MYDOM\jdoe' during authentication, causing access failures. Changing the separator to backslash (or removing it to default to backslash) resolves the issue by aligning with Samba's internal handling of default domain usernames.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Change 'winbind separator' to backslash or remove it to default to backslash
Why this is correct
The separator mismatch causes authentication failures
- ✗
Disable 'winbind use default domain' to force full domain qualification
Why it's wrong here
That would defeat the purpose
- ✗
The valid users line uses quotes around the group name; remove the quotes
Why it's wrong here
Quotes are not the primary issue
- ✗
Enable 'winbind offline logon' to allow cached credentials
Why it's wrong here
Unrelated to the issue
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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.