The answer is to create a security rule with application conditions set to 'facebook-base' and 'youtube' and the action set to 'allow'. This is correct because App-ID enables you to allow only specific applications by explicitly listing them in a rule, while the firewall’s default implicit deny automatically blocks all other traffic that does not match an allow rule. On the PCNSE exam, this tests your understanding of how App-ID rules leverage implicit deny—a common trap is thinking you need a separate block rule, but the default action for unmatched traffic is already deny. The key insight is that you do not need to explicitly block other applications; simply allowing the desired ones achieves the goal. Memory tip: think of it as a “whitelist” approach—only what you name gets through, everything else is stopped by default.
PCNSE Securing Traffic and App-ID Practice Question
This PCNSE practice question tests your understanding of securing traffic and app-id. 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.
A network administrator wants to allow only specific applications such as 'facebook-base' and 'youtube' while blocking all other applications. Which type of security rule should be used to achieve this?
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 application conditions set to 'facebook-base' and 'youtube' and action set to 'allow'.
Option A is correct because App-ID allows you to create a security rule that explicitly allows only the specified applications ('facebook-base' and 'youtube') while implicitly denying all other traffic. Since the default action for any traffic not matching an allow rule is 'deny', this rule achieves the goal of blocking all other applications without needing an explicit block rule.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 application conditions set to 'facebook-base' and 'youtube' and action set to 'allow'.
Why this is correct
This rule allows only the specified applications.
Related concept
Read the scenario before looking for a memorised answer.
✗
Create a security rule with destination port 80 and 443 and action set to 'allow'.
Why it's wrong here
This would allow all HTTP/HTTPS traffic, not just specific applications.
✗
Create a security profile that blocks all applications not in the allow list.
Why it's wrong here
Security profiles apply threats, not application control.
✗
Create a URL filtering rule to allow 'social-networking' and 'multimedia' categories.
Why it's wrong here
URL filtering controls web access, not application identification.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse port-based rules (Option B) with application-based rules, assuming that allowing ports 80/443 is sufficient to control application access, but App-ID is required to distinguish between applications using the same port.
Detailed technical explanation
How to think about this question
Under the hood, App-ID uses multiple identification mechanisms (e.g., protocol decoding, SSL decryption, behavioral analysis) to identify applications regardless of port or protocol. In a real-world scenario, if an organization wants to allow only specific applications like 'facebook-base' and 'youtube' while blocking all others, the security rule must use App-ID conditions because applications can use non-standard ports or be encapsulated within other protocols (e.g., HTTPS on port 443). The implicit deny at the end of the rulebase ensures that any traffic not matching the allow rule is dropped, making an explicit block rule unnecessary.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Securing Traffic and App-ID — This question tests Securing Traffic and App-ID — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create a security rule with application conditions set to 'facebook-base' and 'youtube' and action set to 'allow'. — Option A is correct because App-ID allows you to create a security rule that explicitly allows only the specified applications ('facebook-base' and 'youtube') while implicitly denying all other traffic. Since the default action for any traffic not matching an allow rule is 'deny', this rule achieves the goal of blocking all other applications without needing an explicit block rule.
What should I do if I get this PCNSE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Refer to the exhibit. A network engineer wants to allow only 'ms-update' and 'facebook-base' traffic. After committing the above security policy, they find that 'ssl' traffic is also being allowed. What is the most likely reason?
medium
✓ A.Rule 1 allows all applications because it uses 'application any'.
B.App-ID is not enabled on the firewall.
C.Rule 4 is a deny rule but it is not effective because the traffic is allowed earlier.
D.The rule order is incorrect; rule 3 should be moved before rule 1.
Why A: Rule 1 uses 'application any', which matches all applications regardless of the specific App-ID. Since security policies are evaluated from top to bottom and the first matching rule is applied, any traffic that matches Rule 1's source, destination, and service will be allowed, including 'ssl' traffic. The explicit allow rules for 'ms-update' and 'facebook-base' are irrelevant because Rule 1 catches all traffic first.
Last reviewed: Jun 11, 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.
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