Quick Answer
The answer is /etc/hosts, /etc/nsswitch.conf, and /etc/resolv.conf. These three files control the entire hostname resolution pipeline on a Linux system: /etc/hosts provides static local mappings, /etc/nsswitch.conf defines the order of resolution sources (e.g., files before dns), and /etc/resolv.conf specifies the DNS nameservers to query. When a user cannot resolve hostnames, a misconfiguration in any of these files can break the lookup chain, making them the essential trio to troubleshoot. On the CompTIA Linux+ XK0-005 exam, this question tests your understanding of the Name Service Switch (NSS) mechanism and the priority of resolution methods; a common trap is forgetting that /etc/nsswitch.conf dictates whether the system even consults /etc/hosts or DNS first. To remember the order, think “HNR” — Hosts first, then Nsswitch controls the flow, then Resolv.conf provides the DNS servers.
This XK0-005 practice question tests your understanding of troubleshooting. 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 user is unable to resolve hostnames on a Linux system. Which three configuration files should be checked? (Select THREE).
/etc/hosts
Static mapping of hostnames to IP addresses.
/etc/nsswitch.conf
Defines the order of name resolution sources (e.g., files, dns).
/etc/resolv.conf
Specifies DNS servers and search domains.
/etc/hostname
Why wrong: Stores the local hostname, not involved in name resolution.
/etc/sysconfig/network
Why wrong: Contains network settings but not directly for hostname resolution.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
/etc/hosts
The /etc/hosts file is a static table mapping hostnames to IP addresses, used for local name resolution before or instead of DNS queries. If a user cannot resolve hostnames, this file may be misconfigured or missing entries for the target hostnames, causing resolution failures.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
/etc/hosts
Why this is correct
Static mapping of hostnames to IP addresses.
Related concept
Read the scenario before looking for a memorised answer.
/etc/nsswitch.conf
Why this is correct
Defines the order of name resolution sources (e.g., files, dns).
Related concept
Read the scenario before looking for a memorised answer.
/etc/resolv.conf
Why this is correct
Specifies DNS servers and search domains.
Related concept
Read the scenario before looking for a memorised answer.
/etc/hostname
Why it's wrong here
Stores the local hostname, not involved in name resolution.
/etc/sysconfig/network
Why it's wrong here
Contains network settings but not directly for hostname resolution.
Common exam traps
CompTIA often tests the misconception that /etc/hostname or /etc/sysconfig/network are involved in hostname resolution, when in fact they only affect the local system's identity, not the resolution of external hostnames.
Detailed technical explanation
The Name Service Switch (NSS) in /etc/nsswitch.conf controls the order of resolution sources (e.g., 'hosts: files dns'), so even if /etc/resolv.conf is correct, a misconfigured nsswitch.conf can skip DNS. The resolver library (glibc) reads these files in sequence, and /etc/hosts is checked first if 'files' precedes 'dns' in the order.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the XK0-005 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
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Troubleshooting — This question tests Troubleshooting — Read the scenario before looking for a memorised answer..
The correct answer is: /etc/hosts — The /etc/hosts file is a static table mapping hostnames to IP addresses, used for local name resolution before or instead of DNS queries. If a user cannot resolve hostnames, this file may be misconfigured or missing entries for the target hostnames, causing resolution failures.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
This XK0-005 practice question is part of Courseiva's free CompTIA 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 XK0-005 exam.
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