LFCS Networking Practice Question
A server running Ubuntu 20.04 uses netplan for network configuration. The admin wants to set a static IP address 10.0.0.100/24 on interface enp0s3 with gateway 10.0.0.1 and DNS servers 8.8.8.8 and 8.8.4.4. Which YAML configuration is correct?
⚠ Common exam trap
A common mix-up: candidates confuse the legacy ifupdown syntax (e.g., `address`, `dns-nameservers`) with the required Netplan YAML structure, or forget the mandatory `version: 2` field.
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
✓
network: version: 2 ethernets: enp0s3: addresses: - 10.0.0.100/24 gateway4: 10.0.0.1 nameservers: addresses: [8.8.8.8, 8.8.4.4]
It uses the proper Netplan YAML syntax: `addresses` as a list, `gateway4` for the IPv4 default gateway, and `nameservers` with an `addresses` list. This matches the required static IP 10.0.0.100/24, gateway 10.0.0.1, and DNS servers 8.8.8.8 and 8.8.4.4.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
network: version: 2 ethernets: enp0s3: addresses: - 10.0.0.100/24 gateway: 10.0.0.1 nameservers: addresses: [8.8.8.8, 8.8.4.4]
Why it's wrong here
Incorrect. Uses 'gateway' instead of 'gateway4' for IPv4 default gateway. Netplan requires 'gateway4' for IPv4 and 'gateway6' for IPv6. The nameservers syntax is correct, but the gateway field is wrong.
- ✗
network: version: 2 ethernets: enp0s3: address: 10.0.0.100/24 gateway4: 10.0.0.1 dns-nameservers: 8.8.8.8 8.8.4.4
Why it's wrong here
Incorrect. Uses 'address' (singular) instead of 'addresses' (list) and 'dns-nameservers' which is legacy ifupdown syntax. In Netplan, addresses must be a list, and DNS servers are specified under 'nameservers' with an 'addresses' list.
- ✗
network: ethernets: enp0s3: addresses: 10.0.0.100/24 gateway4: 10.0.0.1 nameservers: addresses: [8.8.8.8, 8.8.4.4]
Why it's wrong here
Incorrect. Missing required 'version: 2' field. Also uses 'addresses: 10.0.0.100/24' without a list (should be a YAML list like '- 10.0.0.100/24'). Even if version were added, the addresses syntax is invalid.
- ✓
network: version: 2 ethernets: enp0s3: addresses: - 10.0.0.100/24 gateway4: 10.0.0.1 nameservers: addresses: [8.8.8.8, 8.8.4.4]
Why this is correct
Correct. Proper Netplan YAML: 'version: 2', 'addresses' as a list, 'gateway4' for IPv4 default gateway, and 'nameservers' with 'addresses' list for DNS servers. All required fields are present and correctly formatted.
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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.