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NetworkinghardMultiple ChoiceObjective-mapped

LFCS Networking Practice Question

Exhibit

Refer to the exhibit.

# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
BOOTPROTO=static
ONBOOT=yes
IPADDR=192.168.1.10
NETMASK=255.255.255.0
GATEWAY=192.168.1.1

Given the network interface configuration in the exhibit, which command should be run to apply the configuration without rebooting?

⚠ Common exam trap

Watch out — candidates often confuse bringing an interface up with applying its configuration, assuming that `ip link set eth0 up` or toggling `ifconfig` will also restore IP settings, when in fact those commands only affect the link state and do not read the persistent configuration file.

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

ifup eth0

The `ifup eth0` command reads the configuration file for the eth0 interface (typically `/etc/sysconfig/network-scripts/ifcfg-eth0` on RHEL/CentOS) and applies the settings (IP address, netmask, gateway, etc.) without requiring a system reboot. This is the standard way to activate a network interface with its configured parameters on Linux systems using the legacy network scripts.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • systemctl restart network

    Why it's wrong here

    Restarts all networking, may be disruptive and not needed.

  • ifup eth0

    Why this is correct

    Brings up the interface with the configuration in ifcfg-eth0.

  • ifconfig eth0 down && ifconfig eth0 up

    Why it's wrong here

    Does not read config file; would need manual assignment.

  • ip link set eth0 up

    Why it's wrong here

    Brings interface up but does not assign IP or route.

Visual reference

192.168.1.0 /24 256 addresses (254 usable) 192.168.1.0 /25 Subnet A 128 addr (126 usable) 192.168.1.128 /25 Subnet B 128 addr (126 usable) Borrowing 1 bit from host portion creates 2 subnets (/25)

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JA

Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

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.