XK0-006 Security Practice Question
An administrator notices that a custom application uses port 8443/TCP. To allow external access, which firewalld command permanently opens this port in the default zone?
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-port=8443/tcp --permanent
The correct command is firewall-cmd --permanent --add-port=8443/tcp. The --permanent flag makes it persistent, --add-port opens the port, and the syntax includes protocol. --add-service is for predefined services, not port numbers.
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 --add-port=8443/tcp --permanent
Why this is correct
Correct. Opens port 8443/tcp permanently.
- ✗
firewall-cmd --add-service=8443/tcp --zone=public --permanent
Why it's wrong here
--add-service expects a service name, not a port.
- ✗
firewall-cmd --add-port=8443 --permanent
Why it's wrong here
Missing protocol (tcp/udp).
- ✗
firewall-cmd --permanent --add-port=8443
Why it's wrong here
Missing protocol.
Go deeper
Related to this question
Learn chapter
System Services and Startup
Key term
firewalld
firewalld is a dynamic firewall management tool for Linux systems that controls incoming and outgoing network traffic using zones and rules.
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.
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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.