Question 387 of 509

Google PCA Practice Question: Analyze and optimize technical and business processes

This PCA practice question tests your understanding of analyze and optimize technical and business processes. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.

Exhibit

{
  "resource": {
    "type": "gce_subnetwork",
    "labels": {
      "subnetwork_name": "default",
      "region": "us-central1"
    }
  },
  "severity": "ERROR",
  "textPayload": "Packet from 10.0.0.1:12345 to 10.0.0.2:80 dropped by firewall policy 'default-deny-ingress'."
}

Refer to the exhibit. The log entry is from Cloud Logging for a VPC subnetwork. What is the most likely cause of this error?

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.

Question 1hardmultiple choice
Review the full subnetting walkthrough →

Exhibit

{
  "resource": {
    "type": "gce_subnetwork",
    "labels": {
      "subnetwork_name": "default",
      "region": "us-central1"
    }
  },
  "severity": "ERROR",
  "textPayload": "Packet from 10.0.0.1:12345 to 10.0.0.2:80 dropped by firewall policy 'default-deny-ingress'."
}

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

A firewall rule blocking ingress on port 80.

The log entry indicates a packet was dropped by a firewall rule. Since the destination is 10.0.0.2 on port 80 (HTTP), the most likely cause is a firewall rule blocking ingress traffic on port 80. In Google Cloud VPC, firewall rules are stateful and evaluated before any routing decisions, so a missing or misconfigured ingress rule for TCP port 80 would cause this drop.

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.

  • A firewall rule blocking ingress on port 80.

    Why this is correct

    The error message attributes the drop to firewall policy 'default-deny-ingress'.

    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 subnetwork default has no internet gateway.

    Why it's wrong here

    Missing internet gateway would cause different errors, not firewall drop.

  • The VM at 10.0.0.2 is not running.

    Why it's wrong here

    The log does not indicate VM state; it specifically mentions firewall drop.

  • The packet is malformed.

    Why it's wrong here

    No indication of malformation; the drop is due to firewall policy.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Google Cloud often tests the distinction between firewall drops and routing failures; the trap here is that candidates may confuse a firewall rule drop with a missing internet gateway or an unreachable VM, but the log entry's 'firewall' field explicitly indicates a firewall decision, not a routing or connectivity issue.

Detailed technical explanation

How to think about this question

Google Cloud VPC firewall rules are implemented as distributed stateful firewalls at the hypervisor level. When a packet is dropped, Cloud Logging records the rule name, direction, and protocol. The log entry's 'disposition: DROP' and 'rule_tag: default-deny-ingress' (or similar) would confirm a firewall rule match. In practice, this often occurs when default-deny-ingress rules are in place and no explicit allow rule for HTTP (tcp:80) exists.

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

An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.

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.

Related practice questions

Related PCA practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

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FAQ

Questions learners often ask

What does this PCA question test?

Analyze and optimize technical and business processes — This question tests Analyze and optimize technical and business processes — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: A firewall rule blocking ingress on port 80. — The log entry indicates a packet was dropped by a firewall rule. Since the destination is 10.0.0.2 on port 80 (HTTP), the most likely cause is a firewall rule blocking ingress traffic on port 80. In Google Cloud VPC, firewall rules are stateful and evaluated before any routing decisions, so a missing or misconfigured ingress rule for TCP port 80 would cause this drop.

What should I do if I get this PCA 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.

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Last reviewed: Jun 30, 2026

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This PCA 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 PCA exam.