LFCS Networking Practice Question
A system administrator is managing a RHEL 8 server that requires a static IP address on interface ens192. The administrator modifies /etc/sysconfig/network-scripts/ifcfg-ens192 to set BOOTPROTO=static, IPADDR=192.168.1.100, PREFIX=24, GATEWAY=192.168.1.1, and DNS1=8.8.8.8. After saving, the administrator runs 'systemctl restart NetworkManager'. The interface obtains the correct static IP and network connectivity works. However, after a reboot of the server, the interface fails to come up with the static IP and instead obtains an IP via DHCP from the local network. The administrator verifies that the DHCP server is active and that the physical connection is good. What is the most likely cause of the issue?
⚠ Common exam trap
Many exam-takers assume setting BOOTPROTO=static and IPADDR is sufficient, overlooking the mandatory ONBOOT=yes parameter required for automatic activation at boot.
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 ONBOOT parameter is set to no or missing in the configuration file.
The ONBOOT parameter controls whether the interface is activated at system boot. If set to 'no' or missing entirely, NetworkManager will not bring up the interface automatically after a reboot, causing it to fall back to DHCP if a DHCP client is active. Setting BOOTPROTO=static and IPADDR correctly only takes effect when ONBOOT=yes is present.
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 kernel parameter nomodeset is set in /etc/default/grub.
Why it's wrong here
nomodeset affects graphics driver loading at boot, having no bearing on interface addressing or DHCP fallback. It is tempting because kernel parameters can influence boot behaviour, and would be relevant when diagnosing display or GPU initialisation failures, but it cannot cause ens192 to obtain a DHCP lease.
- ✗
The firewall is blocking the static IP assignment.
Why it's wrong here
Firewall rules filter network traffic; they do not assign addresses or override ifcfg settings, so blocking cannot explain DHCP fallback after reboot. Firewall misconfiguration would be the cause when connectivity fails despite a correct static address, not when the interface itself requests DHCP.
- ✓
The ONBOOT parameter is set to no or missing in the configuration file.
Why this is correct
ONBOOT=yes is required for the interface to start at boot.
- ✗
The network service is not enabled to start at boot.
Why it's wrong here
NetworkManager already started the interface at boot, so enabling the service would not change the DHCP fallback. The ifcfg file lacks ONBOOT=yes, which NetworkManager reads to decide whether to activate the profile automatically; without it, the interface defaults to DHCP. Enabling a service is the fix when a unit is genuinely disabled, not here.
Visual reference
Go deeper
Related to this question
About these practice questions
Courseiva writes every LFCS question from scratch — 406 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
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.