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Configuring Network ServiceshardMultiple ChoiceObjective-mapped

PCNE Configuring Network Services Practice Question

Exhibit

gcloud compute security-policies describe my-policy --format=json | jq '.rules[] | {priority: .priority, match: .match.config.srcIpRanges, action: .action}'

output:
{"priority":1000,"match":{"config":{"srcIpRanges":["203.0.113.0/24"]}},"action":"allow"}
{"priority":2000,"match":{"config":{"srcIpRanges":["*"],"versionedExpr":"SRC_IPS_V2"}},"action":"deny(403)"}

A company uses Cloud Armor with an external HTTPS load balancer to protect their web application. They have a security policy 'my-policy' attached to the backend service. The policy includes an allow rule (priority 1000) for their corporate IP range (203.0.113.0/24) and a deny rule (priority 2000) for all other IPs. The company has an office at a remote location that uses a different IP range (198.51.100.0/24). Employees from the remote office report they cannot access the application. Meanwhile, employees from the corporate office (203.0.113.0/24) can access. The engineer checks the Cloud Armor policy and sees the rule configuration as shown. What is the most likely cause?

⚠ Common exam trap

Google Cloud often tests the misconception that a deny rule with a higher priority number (e.g., 2000) will override an allow rule with a lower priority number (e.g., 1000), but in reality, Cloud Armor evaluates rules in ascending priority order, so the allow rule is evaluated first and permits matching traffic before the deny rule is considered.

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 remote office IP range is not included in an allow rule in the security policy.

The remote office IP range (198.51.100.0/24) is not explicitly allowed by any rule in the security policy. The only allow rule (priority 1000) permits traffic from the corporate IP range (203.0.113.0/24), and the deny rule (priority 2000) blocks all other IPs. Since the remote office IPs are not covered by the allow rule, they are denied by default, which explains their inability to access the application.

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 rule evaluation order is wrong; the deny rule should have higher priority (lower number).

    Why it's wrong here

    Higher priority rules are evaluated first; the allow rule at 1000 is correct, but it only covers one range.

  • The remote office IP range is not included in an allow rule in the security policy.

    Why this is correct

    Only the corporate IP range is allowed; all others are denied by the default deny rule.

  • The deny rule uses 'SRC_IPS_V2' which is an invalid expression.

    Why it's wrong here

    SRC_IPS_V2 is a valid versioned expression for source IPs.

  • The load balancer's frontend IP blocks traffic from certain geographic regions.

    Why it's wrong here

    The problem is not geographic; it is that the remote office IP is blocked by the deny rule.

Visual reference

Source Router + ACL permit 10.0.0.0/8 deny any Server 10.0.0.5 ✓ 192.168.1.1 ✗ dropped ACLs evaluate top-down; first match wins — implicit deny all at end

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JA

Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

This PCNE 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 PCNE exam.