XK0-006 Security Practice Question
An administrator is configuring iptables on a server. The requirements are: allow incoming SSH (port 22) from the 192.168.1.0/24 network, drop all other incoming traffic, and allow all outgoing traffic. Which three iptables rules achieve this? (Choose THREE.)
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
✓
iptables -A INPUT -p tcp --dport 22 -s 192.168.1.0/24 -j ACCEPT
Default policies: INPUT DROP, OUTPUT ACCEPT. Then allow SSH from subnet.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
iptables -A INPUT -p tcp --dport 22 -s 192.168.1.0/24 -j ACCEPT
Why this is correct
Allows SSH from subnet.
- ✓
iptables -P OUTPUT ACCEPT
Why this is correct
Sets default policy to accept outgoing.
- ✗
iptables -P FORWARD ACCEPT
Why it's wrong here
Not needed; server is not a router.
- ✗
iptables -A INPUT -p tcp --dport 22 -j ACCEPT
Why it's wrong here
This would allow SSH from any source, violating policy.
- ✓
iptables -P INPUT DROP
Why this is correct
Sets default policy to drop incoming.
Visual reference
Go deeper
Related to this question
Learn chapter
File Transfer and Remote Access
Key term
SSH
SSH (Secure Shell) is a cryptographic network protocol that provides secure, encrypted communication and remote administration between two devices over an unsecured network.
Key term
Output
In IT service management, output is the result or deliverable produced by a process, system, or component, such as data, reports, or services delivered to a customer.
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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.