LPIC-2 DNS, Web and Mail Services Practice Question
A system administrator notices that external clients cannot resolve the company's primary website (www.example.com) but internal clients can. What is the most likely cause?
⚠ Common exam trap
Many exam-takers assume the firewall is blocking DNS traffic (Option B) without realizing that external clients query external authoritative servers, not the internal DNS server, so the firewall rule would only affect internal-to-external or external-to-internal queries, not the external resolution path.
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
✓
The external DNS server has a missing A record for www.example.com.
If the external DNS server is missing an A record for www.example.com, external clients querying that server will receive a negative response (NXDOMAIN or NODATA), while internal clients can still resolve the name if the internal DNS server has the correct record (e.g., via zone transfer or manual configuration). This scenario directly explains the symptom: internal resolution works, external fails.
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 internal DNS server is not authoritative for the zone.
Why it's wrong here
An internal server can be authoritative; the problem is external resolution.
- ✗
The firewall is blocking port 53 UDP to the internal DNS server.
Why it's wrong here
This would affect internal clients as well, not just external.
- ✓
The external DNS server has a missing A record for www.example.com.
Why this is correct
External clients query the external authoritative server; if the A record is missing, resolution fails.
- ✗
The internal DNS server is not configured for recursion.
Why it's wrong here
Recursion is not needed for authoritative name resolution; internal clients may still resolve if the server is authoritative.
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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.