Question 395 of 529
Securing TrafficeasyMultiple ChoiceObjective-mapped

PCNSA Securing Traffic Practice Question

This PCNSA practice question tests your understanding of securing traffic. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.

An administrator needs to block all traffic from a specific IP address on the external interface. What is the simplest method?

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

Create a security rule with source zone, source IP, any destination, and action deny, placed at the top of the rulebase.

Option A is correct because creating a security rule with the source zone (external), source IP, any destination, and action deny, placed at the top of the rulebase, is the simplest and most direct method to block all traffic from a specific IP. Option B (Zone Protection profile) is designed for flood protection and not for blocking specific IPs. Option C omits the source zone, which could allow traffic from other zones and is not as precise. Option D (DoS protection policy) is intended for rate limiting and anomaly detection, not for simply blocking a single IP address.

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.

  • Create a security rule with source zone, source IP, any destination, and action deny, placed at the top of the rulebase.

    Why this is correct

    This is straightforward and effective; the rule denies traffic from that IP immediately.

    Related concept

    Standard ACLs match source addresses.

  • Use a Zone Protection profile to block the IP.

    Why it's wrong here

    Zone Protection profiles are for flood protection and packet-based attack prevention, not for simple IP blocking.

  • Create a security rule with source IP address and action deny.

    Why it's wrong here

    Missing source zone – the rule must specify the zone to match the traffic.

  • Use a DoS protection policy to block the IP.

    Why it's wrong here

    DoS protection is for rate limiting and mitigation, not for static block of a specific IP.

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 PCNSA ACL questions on filtering logic and placement.

Related practice questions

Related PCNSA practice-question pages

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FAQ

Questions learners often ask

What does this PCNSA question test?

Securing Traffic — This question tests Securing Traffic — Standard ACLs match source addresses..

What is the correct answer to this question?

The correct answer is: Create a security rule with source zone, source IP, any destination, and action deny, placed at the top of the rulebase. — Option A is correct because creating a security rule with the source zone (external), source IP, any destination, and action deny, placed at the top of the rulebase, is the simplest and most direct method to block all traffic from a specific IP. Option B (Zone Protection profile) is designed for flood protection and not for blocking specific IPs. Option C omits the source zone, which could allow traffic from other zones and is not as precise. Option D (DoS protection policy) is intended for rate limiting and anomaly detection, not for simply blocking a single IP address.

What should I do if I get this PCNSA 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 PCNSA ACL questions on filtering logic and placement.

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 PCNSA practice question is part of Courseiva's free Palo Alto Networks 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 PCNSA exam.