SK0-005 server-administration Practice Question
Network Topology
Refer to the exhibit. A web server is running on port 80, but users are unable to connect. The administrator has confirmed the web server service is running. The output of iptables -L is shown. What is the most likely reason for the connectivity issue?
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 firewall is blocking incoming traffic on port 80
The iptables rules accept only related/established traffic and drop SSH. The catch-all REJECT rule blocks all other incoming connections, including HTTP on port 80, because no explicit ACCEPT rule exists for it.
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 server's default gateway is incorrect
Why it's wrong here
A gateway misconfiguration would affect all outbound traffic, but the firewall rules are the direct cause of blocking inbound port 80.
- ✓
The firewall is blocking incoming traffic on port 80
Why this is correct
The REJECT all rule at the end of the INPUT chain drops any packet not explicitly allowed, including HTTP requests to port 80.
- ✗
SELinux is enforcing and blocking port 80
Why it's wrong here
While SELinux can block ports, the explicit iptables output directly shows a REJECT all rule that denies port 80 traffic.
- ✗
The web server is not bound to the correct IP address
Why it's wrong here
The web server is confirmed running; if it were misbound, local tests would fail, but the issue is external connectivity blocked by the firewall.
Go deeper
Related to this question
Learn chapter
Network Configuration and Connectivity
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
iptables
iptables is a command-line firewall utility in Linux that uses rules to allow or block network traffic based on packet attributes like source IP, destination port, or protocol.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed July 2026 · checked against the official CompTIA exam blueprint
This SK0-005 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 SK0-005 exam.