AWS Certified Solutions Architect - Professional 2020

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networking quiz

Hello. There’s a question with a bad answer on the Networking Quiz.  

The question asks: 

Which of these CIDR blocks and/or IP addresses are invalid for a private VPC or subnet on AWS? (Choose 2)

The possible answers are




D) with subnet mask

Technically B, C, and D are incorrect, but you were looking for B and D. Can you have as a private IP address in AWS? I would think not.

1 Answers

Hi Davetbo,

Why not try it out…  Go out to the VPC console and create a VPC using CIDR.  Then, if that works, create a subnet of  If that works, spin up an EC2 instances in that subnet and manually set the Primary IP to

To really master this stuff, I recommend going out and trying stuff if you’re in doubt about something you see in a question.


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