To create a subnet

This example creates a subnet in the specified VPC with the specified IPv4 CIDR block. We recommend that you let us select an Availability Zone for you. Alternatively, you can use the --availability-zone option to specify the Availability Zone.

Command:

aws ec2 create-subnet --vpc-id vpc-a01106c2 --cidr-block 10.0.1.0/24

Output:

{
    "Subnet": {
      "VpcId": "vpc-a01106c2",
      "AvailableIpAddressCount": 251,
      "MapPublicIpOnLaunch": false,
      "DefaultForAz": false,
      "Ipv6CidrBlockAssociationSet": [],
      "State": "pending",
      "AvailabilityZone": "us-east-1a",
      "SubnetId": "subnet-2c2de375",
      "CidrBlock": "10.0.1.0/24",
      "AssignIpv6AddressOnCreation": false
    }
}

To create a subnet with an IPv6 CIDR block

This example creates a subnet in the specified VPC with the specified IPv4 and IPv6 CIDR blocks (from the ranges of the VPC).

Command:

aws ec2 create-subnet --vpc-id vpc-31896b55 --cidr-block 10.0.0.0/24 --ipv6-cidr-block 2001:db8:1234:a100::/64

Output:

{
  "Subnet": {
      "VpcId": "vpc-31896b55",
      "AvailableIpAddressCount": 251,
      "MapPublicIpOnLaunch": false,
      "DefaultForAz": false,
      "Ipv6CidrBlockAssociationSet": [
          {
              "Ipv6CidrBlock": "2001:db8:1234:a100::/64",
              "AssociationId": "subnet-cidr-assoc-3fe7e347",
              "Ipv6CidrBlockState": {
                  "State": "ASSOCIATING"
              }
          }
      ],
      "State": "pending",
      "AvailabilityZone": "ap-southeast-2a",
      "SubnetId": "subnet-5504d223",
      "CidrBlock": "10.0.0.0/24",
      "AssignIpv6AddressOnCreation": false
  }
}