PCNSE Practice Question: Securing Users and Applications with Authentication
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?
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.
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').
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
A source-user 'unknown' match does not itself block traffic; the firewall treats it as an identity state that can be matched by policy, and blocking depends on the rule action. It is tempting because unknown identity feels like a denial condition, but User-ID unknown is a matchable value, not an implicit deny.
- ✗
The traffic is allowed without authentication because the source-user is 'unknown'.
Why it's wrong here
A security policy rule matching source-user 'unknown' still requires the user to authenticate before the rule permits traffic; Palo Alto Networks resolves unknown users through User-ID, not by granting access. It is tempting because 'unknown' sounds like no identity match, but that value exists precisely so policies can force authentication rather than bypass it.
- ✓
The user is prompted to authenticate via the configured authentication profile.
Why this is correct
Unknown source users trigger the configured authentication profile, forcing a Captive Portal or authentication challenge before access to 192.168.1.0/24 is granted. This satisfies the security policy's requirement to identify unrecognised traffic, since the rule matches unknown source-user and applies the profile rather than silently permitting or dropping the session.
- ✗
The user is redirected to the captive portal.
Why it's wrong here
Captive portal redirect occurs only when a policy rule or authentication profile explicitly enables captive portal for unmatched users; an unknown source-user alone does not trigger redirection. It is tempting because captive portal is the mechanism for identifying unknown users, but it must be configured as an authentication enforcement action, not assumed.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.