How to create a subnet in AWS

If you haven't created the VPC in which you are going to create a new subnet, then check the article here.

A subnet is simply the subset of the IPv4 CIDR block which you defined while creating a VPC. It provides a demarcation for the broadcast domains.

Requirements:

An AWS account
Virtual Private Cloud (VPC) - A subnet always resides in a VPC and hence a VPC should be present prior to creating it
The subnet must be the wholly contained within the IPv4 CIDR block that you defined in the VPC

Steps:

Sign in to your AWS account.
Under Services >> Networking >> VPC
VPC Dashboard >> Your VPCs >> Click on your VPC
Select Subnets >> Click on "Create Subnet"

Details:

Name tag: Name of the subnet (self evident)
VPC: Select the VPC that you want this subnet to be the part of
VPC CIDRs would be automatically populated (since it was defined at the time of VPC creation)
Availability Zone: You get an option to select the AZ (in the same region as that of the VPC), where the subnet should be created. If you select "No preference" Amazon would select the AZ for you, automatically.
IPv4 CIDR block : The actual subnet for which we are doing all this configuration..

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