XK0-006 Security Practice Question
A system administrator is configuring firewalld on a Linux server. They want to allow incoming HTTPS traffic permanently for the public zone. Which command should be used?
⚠ Common exam trap
The trap here is that candidates often forget the `--permanent` flag or confuse the order of arguments, leading them to choose Option A (runtime-only change) or Option B (invalid syntax), while Option C works but is not the best practice for service-based rules.
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
✓
firewall-cmd --add-service=https --zone=public --permanent
The `firewall-cmd --add-service=https --zone=public --permanent` command adds the HTTPS service (TCP port 443) to the public zone and makes the rule persistent across reboots. The `--permanent` flag ensures the change survives a firewall reload or system restart, and the `--zone=public` targets the correct network zone for incoming traffic.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
firewall-cmd --zone=public --add-service=https
Why it's wrong here
This adds the rule but not permanently; it will be lost after reload.
- ✗
firewall-cmd --service=https --add --zone=public --permanent
Why it's wrong here
The syntax is incorrect; --add-service is the correct option.
- ✗
firewall-cmd --add-port=443/tcp --zone=public --permanent
Why it's wrong here
While this also works, the question specifically asks for HTTPS service, and using --add-service is the preferred method.
- ✓
firewall-cmd --add-service=https --zone=public --permanent
Why this is correct
This adds the HTTPS service to the public zone permanently.
Go deeper
Related to this question
Learn chapter
Linux Fundamentals and History
Key term
Service
A service is a software component or system that performs a specific function and is available to be used by other programs or users over a network.
Key term
firewalld
firewalld is a dynamic firewall management tool for Linux systems that controls incoming and outgoing network traffic using zones and rules.
About these practice questions
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This XK0-006 practice question is part of Courseiva's free CompTIA 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 XK0-006 exam.