PCNE Implementing VPC Instances Practice Question
You are deploying a third-party network appliance (e.g., firewall) in a GCP VPC. The appliance requires multiple network interfaces for traffic isolation. You create a VM with three NICs in different subnets. What is a key consideration for routing traffic through the appliance?
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
✓
Custom routes must be created to direct traffic to a specific NIC using the VM's IP as next hop.
Each NIC in a multi-NIC VM is assigned to a different subnet. By default, the VM only sends traffic out of the NIC that matches the destination subnet's route. To route traffic through a specific NIC, custom routes with next hop set to the VM's IP on that NIC are required.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Custom routes must be created to direct traffic to a specific NIC using the VM's IP as next hop.
Why this is correct
This allows traffic to be forwarded to the appliance for inspection.
- ✗
The VM must have an external IP on each NIC.
Why it's wrong here
External IPs are not required for routing.
- ✗
The VM must have IP forwarding disabled.
Why it's wrong here
IP forwarding must be enabled for the VM to route traffic between NICs.
- ✗
All NICs must be in the same subnet.
Why it's wrong here
They must be in different subnets to isolate traffic.
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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.