AWS::EC2::Subnet

• Usually a VPC contains 3 subnets by default. One for each AZ
• The subnet is associated with a VPC and has a CIDR within the range of the CIDR of the VPC
• A subnet is tied to an AZ

• AWS reserves the first 4 and last 1 IPs in each subnet

• Private Subnets usually have a wider range, usually smaller than /20

• Public Subnets do not need wide range, usually /24

• Subnets can have auto-assign Public IP to automatically request a public IP for each service within that subnet

Properties

• https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-ec2-subnet.html

Type: AWS::EC2::Subnet
Properties:
  AssignIpv6AddressOnCreation: Boolean
  AvailabilityZone: String
  AvailabilityZoneId: String
  CidrBlock: String
  EnableDns64: Boolean
  EnableLniAtDeviceIndex: Integer
  Ipv4IpamPoolId: String
  Ipv4NetmaskLength: Integer
  Ipv6CidrBlock: String
  Ipv6IpamPoolId: String
  Ipv6Native: Boolean
  Ipv6NetmaskLength: Integer
  MapPublicIpOnLaunch: Boolean
  OutpostArn: String
  PrivateDnsNameOptionsOnLaunch:
    PrivateDnsNameOptionsOnLaunch
  Tags:
    - Tag
  VpcId: String