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Implementing VPC InstancesmediumMultiple ChoiceObjective-mapped

PCNE Implementing VPC Instances Practice Question

A company is using Cloud NAT to provide outbound internet access for instances without external IPs. They notice that the NAT gateway is running out of ports for connections to a single external IP address. To minimize port exhaustion, what should the engineer configure?

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

Increase the number of NAT IP addresses assigned to the Cloud NAT gateway.

Cloud NAT uses NAT IP addresses and ports. To increase capacity for connections to a single destination IP, you can either allocate more NAT IP addresses (which increases the number of ports) or use dynamic port allocation. Static port allocation is used for endpoints that require predictable source ports. For minimizing exhaustion, adding more NAT IPs is the direct solution.

Answer analysis

Option-by-option breakdown

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

  • Change the NAT port allocation to static.

    Why it's wrong here

    Static allocation reserves ports per VM, which could actually worsen exhaustion.

  • Reduce the endpoint-independent mapping timeout.

    Why it's wrong here

    This might free ports faster but doesn't address the capacity issue as effectively.

  • Enable Cloud NAT logging to diagnose the issue.

    Why it's wrong here

    Logging helps monitor but does not solve port exhaustion.

  • Increase the number of NAT IP addresses assigned to the Cloud NAT gateway.

    Why this is correct

    More NAT IPs provide more source ports, reducing contention.

Visual reference

Inside (Private) PC-A 10.0.0.1 PC-B 10.0.0.2 NAT Router Outside (Public) 203.0.113.1 Inside Global Server PAT: many private IPs share one public IP via unique port numbers

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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.