This LFCS practice question tests your understanding of 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.
A system administrator needs to configure a static IP address on a CentOS 7 server. Which file should be edited to set the IP address permanently?
/etc/netplan/01-netcfg.yaml
Why wrong: Used on Ubuntu 18.04+ with netplan.
/etc/network/interfaces
Why wrong: Used on Debian/Ubuntu, not CentOS.
/etc/hostname
Why wrong: Used for setting hostname, not IP address.
/etc/sysconfig/network-scripts/ifcfg-eth0
Correct file for CentOS 7 static IP configuration.
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/sysconfig/network-scripts/ifcfg-eth0
On CentOS 7, network interfaces are configured via scripts located in /etc/sysconfig/network-scripts/, with each interface having a file named ifcfg-<interface>. The ifcfg-eth0 file stores static IP settings such as IPADDR, NETMASK, and GATEWAY, which are read by the network service (network.service) to apply persistent configuration.
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/netplan/01-netcfg.yaml
Why it's wrong here
Used on Ubuntu 18.04+ with netplan.
/etc/network/interfaces
Why it's wrong here
Used on Debian/Ubuntu, not CentOS.
/etc/hostname
Why it's wrong here
Used for setting hostname, not IP address.
/etc/sysconfig/network-scripts/ifcfg-eth0
Why this is correct
Correct file for CentOS 7 static IP configuration.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates familiar with Ubuntu or Debian systems may incorrectly choose /etc/network/interfaces (Option B) or /etc/netplan/01-netcfg.yaml (Option A), forgetting that CentOS 7 uses the Red Hat-style ifcfg scripts in /etc/sysconfig/network-scripts/.
Detailed technical explanation
The ifcfg files are shell scripts sourced by the network service; they support variables like BOOTPROTO (set to 'static' for manual IP), ONBOOT (to enable at boot), and DNS1/DNS2 for nameservers. Under the hood, the network service parses these files and uses ip commands (e.g., ip addr add) to apply settings, and the configuration persists across reboots via systemd unit dependencies. A subtle behavior: if BOOTPROTO is set to 'dhcp' but IPADDR is also defined, the static IP may be ignored or cause conflicts depending on the order of service startup.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
What to study next
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FAQ
Networking — This question tests Networking — Read the scenario before looking for a memorised answer..
The correct answer is: /etc/sysconfig/network-scripts/ifcfg-eth0 — On CentOS 7, network interfaces are configured via scripts located in /etc/sysconfig/network-scripts/, with each interface having a file named ifcfg-<interface>. The ifcfg-eth0 file stores static IP settings such as IPADDR, NETMASK, and GATEWAY, which are read by the network service (network.service) to apply persistent configuration.
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 25, 2026
This LFCS practice question is part of Courseiva's free Linux Foundation 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 LFCS exam.
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