Question 281 of 516

PCNSE Practice Question: Securing Users and Applications with Authentication

This PCNSE practice question tests your understanding of securing users and applications with authentication. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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

authentication-policy {
    rules {
        "require-auth" {
            match {
                source-user "unknown"
                destination-address "192.168.1.0/24"
            }
            action allow-authentication
            authentication-profile "SAML-Auth"
        }
    }
}

Refer to the exhibit. What happens when a user with an unknown identity (source-user unknown) tries to access resources in 192.168.1.0/24?

Exhibit

authentication-policy {
    rules {
        "require-auth" {
            match {
                source-user "unknown"
                destination-address "192.168.1.0/24"
            }
            action allow-authentication
            authentication-profile "SAML-Auth"
        }
    }
}

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 user is prompted to authenticate via the configured authentication profile.

Option C is correct. When a user with an unknown identity (source-user unknown) attempts to access resources in 192.168.1.0/24 and the policy rule action is 'allow-authentication', the firewall prompts the user to authenticate via the configured authentication profile. Option A is incorrect because the action is not 'deny', so traffic is not blocked solely due to unknown source-user. Option B is incorrect because the traffic is not allowed without authentication; the 'allow-authentication' action requires successful authentication. Option D is incorrect because the action is specifically 'allow-authentication' which triggers an authentication prompt using the configured method (which may be captive portal, but the term 'redirect to captive portal' is less precise than 'prompted to authenticate').

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 traffic is blocked because the source-user is 'unknown'.

    Why it's wrong here

    The policy action is 'allow-authentication', not 'deny'.

  • The traffic is allowed without authentication because the source-user is 'unknown'.

    Why it's wrong here

    The policy matches unknown users and enforces authentication; traffic is not allowed until authentication succeeds.

  • The user is prompted to authenticate via the configured authentication profile.

    Why this is correct

    The 'allow-authentication' action initiates an authentication challenge for the user.

    Related concept

    Standard ACLs match source addresses.

  • The user is redirected to the captive portal.

    Why it's wrong here

    The authentication profile may use SAML, not captive portal.

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 PCNSE ACL questions on filtering logic and placement.

Related practice questions

Related PCNSE practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

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FAQ

Questions learners often ask

What does this PCNSE question test?

Securing Users and Applications with Authentication — This question tests Securing Users and Applications with Authentication — Standard ACLs match source addresses..

What is the correct answer to this question?

The correct answer is: The user is prompted to authenticate via the configured authentication profile. — Option C is correct. When a user with an unknown identity (source-user unknown) attempts to access resources in 192.168.1.0/24 and the policy rule action is 'allow-authentication', the firewall prompts the user to authenticate via the configured authentication profile. Option A is incorrect because the action is not 'deny', so traffic is not blocked solely due to unknown source-user. Option B is incorrect because the traffic is not allowed without authentication; the 'allow-authentication' action requires successful authentication. Option D is incorrect because the action is specifically 'allow-authentication' which triggers an authentication prompt using the configured method (which may be captive portal, but the term 'redirect to captive portal' is less precise than 'prompted to authenticate').

What should I do if I get this PCNSE 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 PCNSE 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 PCNSE 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 PCNSE exam.