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AWS Fundamentals
L1 ConstructAWS::EC2::Subnet

CfnSubnet

Specifies a subnet for the specified VPC. For an IPv4 only subnet, specify an IPv4 CIDR block. If the VPC has an IPv6 CIDR block, you can create an IPv6 only subnet or a dual stack subnet instead. For an IPv6 only subnet, specify an IPv6 CIDR block. For a dual stack subnet, specify both an IPv4 CIDR block and an IPv6 CIDR block. For more information, see [Subnets for your VPC](https://docs.aws.amazon.com/vpc/latest/userguide/configure-subnets.html) in the *Amazon VPC User Guide* .

Import

import { CfnSubnet } from 'aws-cdk-lib/aws-ec2';

Or use the module namespace:

import * as ec2 from 'aws-cdk-lib/aws-ec2';
// ec2.CfnSubnet

Properties

Configuration passed to the constructor as CfnSubnetProps.

vpcIdRequired
string | IVPCRef

The ID of the VPC the subnet is in. If you update this property, you must also update the `CidrBlock` property.

assignIpv6AddressOnCreationOptional
boolean | IResolvable

Indicates whether a network interface created in this subnet receives an IPv6 address. The default value is `false` . If you specify `AssignIpv6AddressOnCreation` , you must also specify an IPv6 CIDR block.

availabilityZoneOptional
string

The Availability Zone of the subnet. If you update this property, you must also update the `CidrBlock` property.

availabilityZoneIdOptional
string

The AZ ID of the subnet.

cidrBlockOptional
string

The IPv4 CIDR block assigned to the subnet. If you update this property, we create a new subnet, and then delete the existing one.

enableDns64Optional
boolean | IResolvable

Indicates whether DNS queries made to the Amazon-provided DNS Resolver in this subnet should return synthetic IPv6 addresses for IPv4-only destinations. > You must first configure a NAT gateway in a public subnet (separate from the subnet containing the IPv6-only workloads). For example, the subnet containing the NAT gateway should have a `0.0.0.0/0` route pointing to the internet gateway. For more information, see [Configure DNS64 and NAT64](https://docs.aws.amazon.com/vpc/latest/userguide/nat-gateway-nat64-dns64.html#nat-gateway-nat64-dns64-walkthrough) in the *Amazon Virtual Private Cloud User Guide* .

enableLniAtDeviceIndexOptional
number

Indicates the device position for local network interfaces in this subnet. For example, `1` indicates local network interfaces in this subnet are the secondary network interface (eth1).

ipv4IpamPoolIdOptional
string

An IPv4 IPAM pool ID for the subnet.

ipv4NetmaskLengthOptional
number

An IPv4 netmask length for the subnet.

ipv6CidrBlockOptional
string

The IPv6 CIDR block. If you specify `AssignIpv6AddressOnCreation` , you must also specify an IPv6 CIDR block.

ipv6IpamPoolIdOptional
string

An IPv6 IPAM pool ID for the subnet.

ipv6NativeOptional
boolean | IResolvable

Indicates whether this is an IPv6 only subnet. For more information, see [Subnet basics](https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Subnets.html#subnet-basics) in the *Amazon Virtual Private Cloud User Guide* .

ipv6NetmaskLengthOptional
number

An IPv6 netmask length for the subnet.

mapPublicIpOnLaunchOptional
boolean | IResolvable

Indicates whether instances launched in this subnet receive a public IPv4 address. The default value is `false` . AWS charges for all public IPv4 addresses, including public IPv4 addresses associated with running instances and Elastic IP addresses. For more information, see the *Public IPv4 Address* tab on the [VPC pricing page](https://docs.aws.amazon.com/vpc/pricing/) .

outpostArnOptional
string

The Amazon Resource Name (ARN) of the Outpost.

privateDnsNameOptionsOnLaunchOptional
any

The hostname type for EC2 instances launched into this subnet and how DNS A and AAAA record queries to the instances should be handled. For more information, see [Amazon EC2 instance hostname types](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-naming.html) in the *Amazon Elastic Compute Cloud User Guide* . Available options: - EnableResourceNameDnsAAAARecord (true | false) - EnableResourceNameDnsARecord (true | false) - HostnameType (ip-name | resource-name)

tagsOptional
CfnTag[]

Any tags assigned to the subnet.

CloudFormation Resource

This L1 construct maps directly to the following CloudFormation resource type.

AWS::EC2::SubnetView in CloudFormation Explorer

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Quick Facts

LevelL1 (CloudFormation)
Moduleaws-ec2
CFN TypeAWS::EC2::Subnet
Properties17

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