LPIC-2 File Sharing and Samba Practice Question
A company is migrating from a workgroup environment to an Active Directory domain. The Samba server is already configured as a domain member using winbind. The administrator wants to ensure that files created by domain users on the Samba server are owned by the corresponding UNIX user accounts derived from the domain. Which idmap backend and configuration is recommended for this purpose?
⚠ Common exam trap
LPI often tests the misconception that `ad` backend is the default or best choice for any domain member, but the question specifically requires deterministic mapping without schema extensions, making `rid` the correct answer.
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
✓
idmap config * : backend = rid
The `rid` backend (option D) is recommended because it generates UNIX UIDs/GIDs deterministically from the Windows RID (Relative Identifier) portion of the user's SID, ensuring that files created by domain users on the Samba server are consistently owned by the same UNIX user accounts derived from the domain. This backend does not require an RFC 2307 schema or LDAP attributes, making it ideal for simple domain member setups where automatic UID/GID mapping is needed.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
idmap config * : backend = ad
Why it's wrong here
This requires RFC2307 attributes in AD.
- ✗
idmap config * : backend = tdb
Why it's wrong here
This stores ID mappings in a local tdb file, not consistent across servers.
- ✗
idmap config * : backend = autorid
Why it's wrong here
This auto-assigns IDs per domain, but not consistent.
- ✓
idmap config * : backend = rid
Why this is correct
This derives UIDs from RIDs for consistent mapping.
Go deeper
Related to this question
About these practice questions
One of 507 original LPIC-2 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
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.