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XK0-006 Practice Question: A security policy requires that SSH access be…

A security policy requires that SSH access be allowed only from the internal management subnet 10.10.10.0/24. Which firewalld rich rule should be added?

⚠ Common exam trap

Candidates often confuse `--add-source` (which binds a source to a zone) with a rule filter, or they think `--add-port` combined with `--add-source` creates a source-restricted port rule, when in fact firewalld requires a rich rule to enforce source-based service restrictions.

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-rich-rule='rule family="ipv4" source address="10.10.10.0/24" service name="ssh" accept'

It uses the firewalld rich-rule syntax to explicitly define an IPv4 rule that accepts SSH traffic only from the 10.10.10.0/24 source subnet. Rich rules provide granular control over source addresses, services, and actions, which is required by the security policy. The `--add-rich-rule` option allows specifying the rule family, source address, service name, and accept action in a single, persistent rule.

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 --permanent --add-port=22/tcp --add-source=10.10.10.0/24

    Why it's wrong here

    This adds source address and port as separate rules; the source does not restrict the port rule.

  • firewall-cmd --add-rich-rule='rule family="ipv4" source address="10.10.10.0/24" service name="ssh" accept'

    Why this is correct

    This rich rule binds the source address to the SSH service.

  • firewall-cmd --add-source=10.10.10.0/24 --add-service=ssh

    Why it's wrong here

    This adds the source and service separately, but does not link them; all sources can access SSH.

  • iptables -A INPUT -s 10.10.10.0/24 -p tcp --dport 22 -j ACCEPT

    Why it's wrong here

    While this iptables command works, the question asks for a firewalld command.

Visual reference

192.168.1.0 /24 256 addresses (254 usable) 192.168.1.0 /25 Subnet A 128 addr (126 usable) 192.168.1.128 /25 Subnet B 128 addr (126 usable) Borrowing 1 bit from host portion creates 2 subnets (/25)

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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.