# IpAddresses

An abstract Provider of IpAddresses.

Note this is specific to the IPv4 CIDR.

- Source: [`aws-ec2/lib/ip-addresses.ts`](https://github.com/aws/aws-cdk/blob/v2.275.0/packages/aws-cdk-lib/aws-ec2/lib/ip-addresses.ts#L15)
- Type last changed: v2.48.0 · 27 Oct 2022

## Example

```ts
const vpc = new ec2.Vpc(this, 'TheVPC', {
  // 'IpAddresses' configures the IP range and size of the entire VPC.
  // The IP space will be divided based on configuration for the subnets.
  ipAddresses: ec2.IpAddresses.cidr('10.0.0.0/21'),

  // 'maxAzs' configures the maximum number of availability zones to use.
  // If you want to specify the exact availability zones you want the VPC
  // to use, use `availabilityZones` instead.
  maxAzs: 3,

  // 'subnetConfiguration' specifies the "subnet groups" to create.
  // Every subnet group will have a subnet for each AZ, so this
  // configuration will create `3 groups × 3 AZs = 9` subnets.
  subnetConfiguration: [
    {
      // 'subnetType' controls Internet access, as described above.
      subnetType: ec2.SubnetType.PUBLIC,

      // 'name' is used to name this particular subnet group. You will have to
      // use the name for subnet selection if you have more than one subnet
      // group of the same type.
      name: 'Ingress',

      // 'cidrMask' specifies the IP addresses in the range of individual
      // subnets in the group. Each of the subnets in this group will contain
      // `2^(32 address bits - 24 subnet bits) - 2 reserved addresses = 254`
      // usable IP addresses.
      //
      // If 'cidrMask' is left out the available address space is evenly
      // divided across the remaining subnet groups.
      cidrMask: 24,
    },
    {
      cidrMask: 24,
      name: 'Application',
      subnetType: ec2.SubnetType.PRIVATE_WITH_EGRESS,
    },
    {
      cidrMask: 28,
      name: 'Database',
      subnetType: ec2.SubnetType.PRIVATE_ISOLATED,

      // 'reserved' can be used to reserve IP address space. No resources will
      // be created for this subnet, but the IP range will be kept available for
      // future creation of this subnet, or even for future subdivision.
      reserved: true
    }
  ],
});
```

## Methods

- `awsIpamAllocation(props: AwsIpamProps): IIpAddresses` (static) — Used to provide centralized Ip Address Management services for your VPC.

  Uses VPC CIDR allocations from AWS IPAM

  Note this is specific to the IPv4 CIDR.

- `cidr(cidrBlock: string): IIpAddresses` (static) — Used to provide local Ip Address Management services for your VPC.

  VPC CIDR is supplied at creation and subnets are calculated locally

  Note this is specific to the IPv4 CIDR.