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Implementing VPC InstancesmediumMultiple ChoiceObjective-mapped

PCNE Implementing VPC Instances Practice Question

An engineer is deploying a network appliance (e.g., a firewall) in a VPC. The appliance needs to handle traffic between different subnets. How many network interfaces should the appliance VM have, and why?

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

Two NICs: one for management, one for data traffic

Network appliances often use multiple NICs for traffic segregation: one for management, others for data traffic. Each NIC can be in a different subnet. NIC0 is the primary and must be connected. Up to 8 NICs are supported.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Zero NICs: use an internal load balancer

    Why it's wrong here

    A VM must have at least one NIC to be functional. An internal load balancer can distribute traffic to VMs but does not replace the VM's network interface.

  • One NIC, with IP forwarding enabled

    Why it's wrong here

    A single NIC can forward traffic but does not provide separation between management and data planes, which is a best practice for network appliances.

  • Two NICs: one for management, one for data traffic

    Why this is correct

    Multiple NICs allow separation of management and data traffic. The management NIC can be used for SSH/API access, while data NICs handle forwarded traffic.

  • Three NICs: one for each subnet it routes between

    Why it's wrong here

    While possible, the minimum and typical setup is two NICs. Subnets can be reached via routes, so separate NIC per subnet is not necessary.

Visual reference

192.168.1.0 /24 256 addresses (254 usable) 192.168.1.0 /25 Subnet A 128 addr (126 usable) 192.168.1.128 /25 Subnet B 128 addr (126 usable) Borrowing 1 bit from host portion creates 2 subnets (/25)

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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.