PCNSE Core Concepts and Architecture Practice Question
A firewall administrator is configuring a new security zone for a DMZ. The requirement is that the DMZ zone should not be able to initiate connections to the internal trusted zone, but the trusted zone should be able to initiate connections to the DMZ. Which configuration achieves this with the least administrative effort?
⚠ Common exam trap
The trap here is believing that an explicit deny rule is required to block traffic between zones, when the implicit deny already handles it.
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 policy from trust to DMZ allowing the required applications, and rely on the implicit deny for DMZ to trust.
The default security posture of a Palo Alto Networks firewall is to deny all interzone traffic except intrazone traffic. By creating only the necessary allow rule from trust to DMZ, the administrator ensures that the trusted zone can initiate connections to the DMZ, while the DMZ cannot initiate connections to the trust zone because of the implicit deny. This minimizes configuration and reduces the risk of misconfiguration.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Assign the DMZ interface to the same zone as the trust interface, and use security policies to control traffic between them.
Why it's wrong here
Placing the DMZ interface in the same zone as the trust interface would allow all traffic between them by default, since intrazone traffic is permitted by the default intrazone rule. This would violate the requirement and is not a valid segmentation practice, as it eliminates the security boundary between the DMZ and the internal network.
- ✓
Create a security policy from trust to DMZ allowing the required applications, and rely on the implicit deny for DMZ to trust.
Why this is correct
The firewall's default behavior is to deny interzone traffic unless explicitly allowed. By creating only the trust-to-DMZ allow policy, the administrator leverages the implicit deny rule to block DMZ-to-trust traffic. This is the simplest and most efficient configuration, requiring only one policy.
- ✗
Create two security policies: one from trust to DMZ allowing all applications, and one from DMZ to trust denying all applications.
Why it's wrong here
Creating an explicit deny policy from DMZ to trust is not necessary because the default interzone behavior is to deny. This approach adds an extra policy that must be managed, increasing administrative effort without providing additional security, as the implicit deny at the end of the rulebase already blocks the traffic.
- ✗
Configure the DMZ zone with a zone protection profile that blocks all traffic from the DMZ to the trust zone.
Why it's wrong here
Zone protection profiles are used to defend against flood attacks and reconnaissance, not to enforce security policy between zones. They do not control which zones can initiate connections, so this configuration would not achieve the desired traffic control and could interfere with legitimate traffic.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Palo Alto Networks exam blueprint
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.