- A
The /etc/hosts file contains an entry that overrides the DNS resolution for external domains.
Why wrong: An override in hosts would affect all resolution for that hostname, not just external.
- B
The nmblookup service is not running.
Why wrong: nmblookup is for NetBIOS name resolution, not DNS.
- C
The search domain in /etc/resolv.conf is incorrect, causing the resolver to append an inappropriate domain to queries.
An incorrect search domain can cause the resolver to try invalid fully qualified domain names, leading to resolution failures for external hosts.
- D
The /etc/nsswitch.conf file is missing the 'dns' service in the 'hosts' line.
Why wrong: Missing dns would prevent any DNS resolution, but the question states ping to internal IPs works, so DNS is partially working.
Quick Answer
The answer is an incorrect search domain in /etc/resolv.conf. When a search domain is misconfigured, the resolver appends that domain to any single-label hostname before querying the DNS server, but it can also interfere with fully qualified domain names if the query is not terminated with a trailing dot. This causes the resolver to send malformed queries like 'externaldomain.com.wrong.domain' instead of the intended FQDN, leading to resolution failures even though the DNS server itself is valid and internal IPs remain reachable. On the LPIC-2 exam, this scenario tests your understanding of the resolver’s search path behavior, a common trap where candidates focus on the DNS server or firewall instead of the resolver logic. Remember the memory tip: “A trailing dot stops the rot”—always ensure FQDNs end with a dot to prevent the search domain from being appended.
LPIC-2 Network Client Management Practice Question
This LPIC-2 practice question tests your understanding of network client management. 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 Linux client is unable to resolve hostnames for external domains but can ping internal hosts by IP. The /etc/resolv.conf file is correctly configured with a valid DNS server. 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 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 search domain in /etc/resolv.conf is incorrect, causing the resolver to append an inappropriate domain to queries.
Option C is correct because when a search domain is incorrectly configured in /etc/resolv.conf, the resolver appends that domain to single-label hostnames before querying the DNS server. For external fully qualified domain names (FQDNs), this can cause the resolver to send queries like 'externaldomain.com.incorrect.domain' instead of the intended domain, leading to resolution failures. Since internal IPs are reachable (bypassing DNS) and the DNS server itself is valid, the issue is most likely the resolver's domain search behavior.
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 /etc/hosts file contains an entry that overrides the DNS resolution for external domains.
Why it's wrong here
An override in hosts would affect all resolution for that hostname, not just external.
- ✗
The nmblookup service is not running.
Why it's wrong here
nmblookup is for NetBIOS name resolution, not DNS.
- ✓
The search domain in /etc/resolv.conf is incorrect, causing the resolver to append an inappropriate domain to queries.
Why this is correct
An incorrect search domain can cause the resolver to try invalid fully qualified domain names, leading to resolution failures for external hosts.
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 /etc/nsswitch.conf file is missing the 'dns' service in the 'hosts' line.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume a misconfigured /etc/resolv.conf means the DNS server is wrong or unreachable, but the question explicitly states it is correctly configured with a valid server, so the issue must be in how the resolver processes queries, specifically the search domain or ndots behavior.
Detailed technical explanation
How to think about this question
The resolver's behavior is defined by the 'search' directive in /etc/resolv.conf (per RFC 1536 and glibc's resolver implementation). When a hostname contains no dots, the resolver tries appending each search domain in order before falling back to the unmodified name. A common real-world scenario is misconfiguring the search domain as 'local' or 'internal.corp' when the client is not in that domain, causing all external queries to be mangled. The 'ndots' option (default 1) also influences this: if the hostname has fewer dots than ndots, search domains are tried first.
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.
- →
Network Client Management — study guide chapter
Learn the concepts, then practise the questions
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Network Client Management practice questions
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FAQ
Questions learners often ask
What does this LPIC-2 question test?
Network Client Management — This question tests Network Client Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The search domain in /etc/resolv.conf is incorrect, causing the resolver to append an inappropriate domain to queries. — Option C is correct because when a search domain is incorrectly configured in /etc/resolv.conf, the resolver appends that domain to single-label hostnames before querying the DNS server. For external fully qualified domain names (FQDNs), this can cause the resolver to send queries like 'externaldomain.com.incorrect.domain' instead of the intended domain, leading to resolution failures. Since internal IPs are reachable (bypassing DNS) and the DNS server itself is valid, the issue is most likely the resolver's domain search behavior.
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
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Last reviewed: Jun 11, 2026
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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