PCNE Practice Question: Managing, Monitoring, and Optimising Network Operations
A security team wants to capture and analyze all DNS queries from their Compute Engine instances to detect potential data exfiltration. They have enabled VPC Flow Logs. Which TWO additional steps should they take to capture DNS query details?
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
✓
Enable Packet Mirroring on the instances
VPC Flow Logs do not include DNS query names. To capture DNS queries, they need to enable DNS logging (which logs queries sent to Cloud DNS) or use Packet Mirroring to capture the full DNS packets for analysis.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Enable Packet Mirroring on the instances
Why this is correct
Packet Mirroring copies all traffic, including DNS packets, for deep analysis.
- ✓
Enable Cloud DNS logging
Why this is correct
Cloud DNS logging captures DNS query names sent to Cloud DNS resolvers.
- ✗
Enable firewall rule logging
Why it's wrong here
Firewall rule logging does not capture DNS queries.
- ✗
Increase VPC Flow Logs sampling rate to 100%
Why it's wrong here
VPC Flow Logs do not contain DNS query names even at 100% sampling.
- ✗
Export VPC Flow Logs to BigQuery
Why it's wrong here
Exporting to BigQuery does not add DNS query names.
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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.