Question 448 of 499
TroubleshootingmediumMultiple ChoiceObjective-mapped

Quick Answer

The answer is that the firewall rule order is incorrect, because cloud firewalls process rules sequentially from top to bottom, and the first rule blocking all SSH traffic from any source is evaluated before the second rule permitting SSH from the internal 10.0.0.0/16 network. This means any SSH attempt from outside that range—such as from a remote location—is dropped immediately, never reaching the permissive rule. On the CompTIA Cloud+ CV0-004 exam, this scenario tests your understanding of stateful versus stateless filtering and the critical importance of rule sequencing in cloud security groups. A common trap is assuming that a permissive rule later in the list will override an earlier deny, but firewalls stop at the first match. Remember the mnemonic “First match wins, so place your permits before your denies” to avoid this misconfiguration.

CV0-004 Troubleshooting Practice Question

This CV0-004 practice question tests your understanding of troubleshooting. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

Exhibit

iptables -L -v -n
Chain INPUT (policy ACCEPT)
 pkts bytes target     prot opt in     out     source               destination
    0     0 DROP       tcp  --  eth0   *       0.0.0.0/0            10.0.1.10  tcp dpt:22
    5   600 ACCEPT     tcp  --  eth0   *       10.0.0.0/16          10.0.1.10  tcp dpt:22

Refer to the exhibit. An administrator is unable to SSH into a cloud server with IP 10.0.1.10 from a remote location (outside the 10.0.0.0/16 network). What is the most likely cause?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "most likely"

    Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

Question 1mediummultiple choice
Full question →

Exhibit

iptables -L -v -n
Chain INPUT (policy ACCEPT)
 pkts bytes target     prot opt in     out     source               destination
    0     0 DROP       tcp  --  eth0   *       0.0.0.0/0            10.0.1.10  tcp dpt:22
    5   600 ACCEPT     tcp  --  eth0   *       10.0.0.0/16          10.0.1.10  tcp dpt:22

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 rule order is incorrect

Option D is correct because firewall rules are evaluated in order; the first rule drops all SSH traffic from any source, then the second only permits internal traffic. Option A is wrong because the error is not about the SSH service. Option B is wrong because the second rule shows some packets accepted. Option C is wrong because host key issues would cause a different error.

Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.

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 firewall rule order is incorrect

    Why this is correct

    The drop rule appears before the allow rule, so external traffic is dropped before reaching the allow rule.

    Clue confirmation

    The clue word "most likely" in the question point toward this answer.

    Related concept

    Standard ACLs match source addresses.

  • The firewall is dropping all packets on port 22

    Why it's wrong here

    The second rule accepts SSH from internal network, so not all packets are dropped.

  • The SSH host key has changed

    Why it's wrong here

    A changed host key would cause a warning, not a connection failure.

  • The SSH service is not running

    Why it's wrong here

    The SSH service might be running but blocked by firewall.

Common exam traps

Common exam trap: ACLs stop at the first match

ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.

Detailed technical explanation

How to think about this question

ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.

KKey Concepts to Remember

  • Standard ACLs match source addresses.
  • Extended ACLs can match source, destination, protocol and ports.
  • The first matching ACL entry is used.
  • There is usually an implicit deny at the end.

TExam Day Tips

  • Check inbound versus outbound direction.
  • Read the ACL from top to bottom.
  • Look for a broader permit or deny above the intended line.

Key takeaway

ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.

Real-world example

How this comes up in practice

A security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.

What to study next

Got this wrong? Here's your next step.

Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related CV0-004 ACL questions on filtering logic and placement.

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Related CV0-004 practice-question pages

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FAQ

Questions learners often ask

What does this CV0-004 question test?

Troubleshooting — This question tests Troubleshooting — Standard ACLs match source addresses..

What is the correct answer to this question?

The correct answer is: The firewall rule order is incorrect — Option D is correct because firewall rules are evaluated in order; the first rule drops all SSH traffic from any source, then the second only permits internal traffic. Option A is wrong because the error is not about the SSH service. Option B is wrong because the second rule shows some packets accepted. Option C is wrong because host key issues would cause a different error.

What should I do if I get this CV0-004 question wrong?

Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related CV0-004 ACL questions on filtering logic and placement.

Are there clue words in this question I should notice?

Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

What is the key concept behind this question?

Standard ACLs match source addresses.

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Last reviewed: Jun 24, 2026

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This CV0-004 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 CV0-004 exam.