The answer is that another rule with a lower priority number that allows all traffic is overriding the deny rule. In Cloud Armor, rules are evaluated sequentially based on priority, where a lower numeric value means higher precedence; a rule with priority 1000 allowing all traffic will be matched and enforced before a deny rule with priority 2000, effectively bypassing the intended block. This scenario tests your understanding of Cloud Armor rule evaluation order, a common trap on the Google Professional Cloud Security Engineer exam where candidates mistakenly assume deny rules automatically take effect regardless of priority. The key insight is that Cloud Armor stops evaluating rules as soon as it finds a match, so a broad allow rule with higher precedence will always win over a more specific deny rule with lower precedence. Remember the memory tip: lower number wins the fight, so check your priority ladder before blaming the rule logic.
PCSE Configuring network security Practice Question
This PCSE practice question tests your understanding of configuring network security. 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 company uses Cloud Armor to protect an external HTTPS load balancer. They want to block requests from a specific IP address range 198.51.100.0/24, but allow all other traffic. After creating a deny rule with the source IP condition, they notice that requests from that range are still reaching the backend. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Another rule with a lower priority number that allows all traffic is overriding the deny rule.
In Cloud Armor, rules are evaluated in order of priority, where lower priority numbers indicate higher precedence. If a rule with a lower priority number (e.g., 1000) allows all traffic, it will be evaluated before a deny rule with a higher priority number (e.g., 2000), causing the deny rule to be overridden. This is the most likely reason the specific IP range is still reaching the backend despite the deny rule being created.
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.
✓
Another rule with a lower priority number that allows all traffic is overriding the deny rule.
Why this is correct
Rules are evaluated in priority order; lower number wins. A default allow rule with priority 1000 might override a deny rule with higher priority.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The rule action is set to 'allow' instead of 'deny'.
Why it's wrong here
If action were 'allow', it would not block traffic. But the scenario says they created a deny rule.
✗
Cloud Armor cannot block traffic based on source IP; it only supports geographic and header-based conditions.
Why it's wrong here
Cloud Armor supports source IP filtering.
✗
The rule uses the wrong match syntax, such as 'sourceIpRange' instead of 'inIpRange'.
Why it's wrong here
The correct syntax is 'inIpRange'; a wrong syntax would result in a parsing error.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the concept that priority numbers in Cloud Armor are evaluated from lowest to highest, and candidates mistakenly think a deny rule with a higher priority number will take precedence over an allow rule with a lower priority number.
Trap categories for this question
Scenario analysis trap
If action were 'allow', it would not block traffic. But the scenario says they created a deny rule.
Detailed technical explanation
How to think about this question
Cloud Armor security policies use a priority-based evaluation model where rules are sorted by priority number (lower number = higher priority) and the first matching rule's action is applied. This is analogous to firewallACL evaluation in networking, where a deny rule can be rendered ineffective if a higher-priority allow rule matches first. In real-world scenarios, this often happens when default allow rules (e.g., priority 1000) are left in place after adding custom deny rules, leading to unexpected traffic flow.
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 cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
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.
Configuring network security — This question tests Configuring network security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Another rule with a lower priority number that allows all traffic is overriding the deny rule. — In Cloud Armor, rules are evaluated in order of priority, where lower priority numbers indicate higher precedence. If a rule with a lower priority number (e.g., 1000) allows all traffic, it will be evaluated before a deny rule with a higher priority number (e.g., 2000), causing the deny rule to be overridden. This is the most likely reason the specific IP range is still reaching the backend despite the deny rule being created.
What should I do if I get this PCSE 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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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. A company uses Cloud Armor to protect their HTTP Load Balancer from DDoS attacks. They want to block requests from a specific malicious IP address range, 203.0.113.0/24. Which Cloud Armor policy configuration should they use?
easy
A.Create an allow rule with source IP condition for their own IP ranges and rely on default deny.
B.Create a rule with a 'source-ip' tag set to 'malicious' and assign to the load balancer.
C.Create a deny rule with priority 1000000 for the IP range.
✓ D.Create a deny rule with a source IP condition for 203.0.113.0/24 and set priority to 1000.
Why D: Option D is correct because Cloud Armor security policies use priority-based rules, where lower numbers indicate higher priority. A deny rule with priority 1000 for the specific IP range 203.0.113.0/24 ensures that traffic from that range is blocked before any lower-priority allow rules are evaluated. This is the standard method to block specific IP ranges while allowing other traffic.
Last reviewed: Jun 30, 2026
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This PCSE practice question is part of Courseiva's free Google Cloud 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 PCSE exam.
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