This is the new *Amazon CloudFormation Template Reference Guide*. Please update your bookmarks and links. For help getting started with CloudFormation, see the [Amazon CloudFormation User Guide](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/Welcome.html).

# AWS::EC2::LaunchTemplate Ipv4PrefixSpecification
<a name="aws-properties-ec2-launchtemplate-ipv4prefixspecification"></a>

Specifies an IPv4 prefix for a network interface.

`Ipv4PrefixSpecification` is a property of [AWS::EC2::LaunchTemplate NetworkInterface](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-launchtemplate-networkinterface.html).

## Syntax
<a name="aws-properties-ec2-launchtemplate-ipv4prefixspecification-syntax"></a>

To declare this entity in your Amazon CloudFormation template, use the following syntax:

### JSON
<a name="aws-properties-ec2-launchtemplate-ipv4prefixspecification-syntax.json"></a>

```
{
  "[Ipv4Prefix](#cfn-ec2-launchtemplate-ipv4prefixspecification-ipv4prefix)" : String
}
```

### YAML
<a name="aws-properties-ec2-launchtemplate-ipv4prefixspecification-syntax.yaml"></a>

```
  [Ipv4Prefix](#cfn-ec2-launchtemplate-ipv4prefixspecification-ipv4prefix): String
```

## Properties
<a name="aws-properties-ec2-launchtemplate-ipv4prefixspecification-properties"></a>

`Ipv4Prefix`  <a name="cfn-ec2-launchtemplate-ipv4prefixspecification-ipv4prefix"></a>
The IPv4 prefix. For information, see [ Assigning prefixes to network interfaces](https://docs.amazonaws.cn/AWSEC2/latest/UserGuide/ec2-prefix-eni.html) in the *Amazon EC2 User Guide*.  
*Required*: No  
*Type*: String  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)