The answer is to create a security policy to block the IP and commit. This is the best practice because a security policy leverages the firewall’s stateful inspection engine to deny all traffic from that external IP at the network layer, making the block persistent across reboots and all interfaces, unlike temporary session-based blocks. On the Palo Alto Networks Certified Network Security Administrator PCNSA exam, this scenario tests your understanding of policy-based versus dynamic blocking—a common trap is confusing a dynamic block list (which is session-specific and non-persistent) with a committed security policy rule. Remember, for permanent, infrastructure-wide blocks, you must use a security policy rule with a source address of the IP and an action of deny, then commit. Memory tip: “Policy for permanent, dynamic for temporary”—if the log shows repeated failures, commit a policy to make it stick.
PCNSA Device Management and Services Practice Question
This PCNSA practice question tests your understanding of device management and services. 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 notices repeated login failures from external IP 10.0.0.1 in the system logs. The admin wants to permanently block all traffic from that IP. Which approach is best practice?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
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 to block the IP and commit
Option A is correct because creating a security policy to block the IP and committing it is the standard, persistent method to block all traffic from a specific external IP address in Palo Alto Networks firewalls. This approach uses the firewall's stateful inspection engine to deny traffic at the network layer, ensuring the block survives reboots and is enforced across all interfaces.
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 policy to block the IP and commit
Why this is correct
A security policy denies all traffic from that IP through the firewall.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use the admin lockout feature
Why it's wrong here
Only prevents admin login attempts, not general traffic.
✗
Create a static route to null0 via CLI
Why it's wrong here
Does not block traffic; routing is not the issue.
✗
Use a Zone Protection profile
Why it's wrong here
Zone Protection handles flood protection, not a specific IP block.
✗
Add the IP to a block list in the management profile
Why it's wrong here
Only restricts management access, not data traffic.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is confusing management-plane controls (like admin lockout or management profile block lists) with data-plane traffic controls, leading candidates to select options that only restrict administrative access rather than blocking all traffic from the IP.
Detailed technical explanation
How to think about this question
Under the hood, a security policy blocking an IP creates an entry in the firewall's rulebase that is evaluated during the first packet of a session. The firewall uses a fast-path lookup to match the source IP against the policy, and if denied, the session is dropped without further processing. In real-world scenarios, this approach is preferred over ACLs or route-based blocks because it integrates with logging, reporting, and dynamic block lists (e.g., via External Dynamic Lists or PAN-DB).
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 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.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Device Management and Services — This question tests Device Management and Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create a security policy to block the IP and commit — Option A is correct because creating a security policy to block the IP and committing it is the standard, persistent method to block all traffic from a specific external IP address in Palo Alto Networks firewalls. This approach uses the firewall's stateful inspection engine to deny traffic at the network layer, ensuring the block survives reboots and is enforced across all interfaces.
What should I do if I get this PCNSA question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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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.
Question Discussion
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