Quick Answer
The answer is /etc/nsswitch.conf, along with /etc/hosts and /etc/resolv.conf, as the three key files used in the DNS resolution process on Linux. The Name Service Switch (NSS) configuration file, /etc/nsswitch.conf, defines the order in which different sources—such as local files, DNS, or NIS—are consulted for hostname resolution, making it the central control point for the entire lookup flow. On the LPIC-1 exam, this topic tests your understanding of how the system resolves names before reaching out to a DNS server, often appearing in questions that ask you to identify which files influence resolution order or caching. A common trap is confusing /etc/host.conf with /etc/nsswitch.conf; remember that modern Linux systems rely on nsswitch.conf, while host.conf is legacy from older glibc versions. Memory tip: think of “NSS” as “Name Source Switch”—it switches between hosts, DNS, and other sources to resolve a name.
This LPIC-1 practice question tests your understanding of essential system services and networking. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
Which THREE of the following are valid files or directories used by the Domain Name System (DNS) resolution process on a Linux system?
/etc/host.conf
Specifies resolver options like order and multi.
/etc/resolv.conf
Lists DNS servers and search domains.
/etc/named.conf
Why wrong: Configuration for BIND DNS server, not client-side resolver.
/etc/sysconfig/network
Why wrong: Used for network interface configuration on some distros, not DNS resolution.
/etc/nsswitch.conf
Controls order of name resolution methods (e.g., files, dns).
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/host.conf
Option A is correct because `/etc/host.conf` controls the order in which hostname resolution methods are tried (e.g., 'order hosts,bind'), directly influencing whether the system queries DNS or checks local files first. This file is part of the glibc resolver's configuration and is consulted during the DNS resolution process on Linux.
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/host.conf
Why this is correct
Specifies resolver options like order and multi.
Related concept
Read the scenario before looking for a memorised answer.
/etc/resolv.conf
Why this is correct
Lists DNS servers and search domains.
Related concept
Read the scenario before looking for a memorised answer.
/etc/named.conf
Why it's wrong here
Configuration for BIND DNS server, not client-side resolver.
/etc/sysconfig/network
Why it's wrong here
Used for network interface configuration on some distros, not DNS resolution.
/etc/nsswitch.conf
Why this is correct
Controls order of name resolution methods (e.g., files, dns).
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates confuse server-side DNS configuration files (like `/etc/named.conf`) with client-side resolution files, or they overlook `/etc/host.conf` and `/etc/nsswitch.conf` as essential parts of the DNS resolution chain.
Detailed technical explanation
The DNS resolution process on Linux involves multiple layers: the glibc resolver (using `/etc/resolv.conf` for nameserver IPs, `/etc/host.conf` for resolution order, and `/etc/nsswitch.conf` to determine which databases to consult) and the Name Service Switch (NSS) framework, which allows pluggable modules like `systemd-resolved` or `nss-dns`. A real-world scenario is when a misconfigured `/etc/host.conf` with 'order hosts,bind' causes local `/etc/hosts` entries to override DNS, leading to unexpected resolution failures.
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 LPIC-1 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
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FAQ
Essential System Services and Networking — This question tests Essential System Services and Networking — Read the scenario before looking for a memorised answer..
The correct answer is: /etc/host.conf — Option A is correct because `/etc/host.conf` controls the order in which hostname resolution methods are tried (e.g., 'order hosts,bind'), directly influencing whether the system queries DNS or checks local files first. This file is part of the glibc resolver's configuration and is consulted during the DNS resolution process on Linux.
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 11, 2026
This LPIC-1 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-1 exam.
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