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

# AWS::NetworkFirewall::Firewall SubnetMapping
<a name="aws-properties-networkfirewall-firewall-subnetmapping"></a>

The ID for a subnet that you want to associate with the firewall. AWS Network Firewall creates an instance of the associated firewall in each subnet that you specify, to filter traffic in the subnet's Availability Zone.

## Syntax
<a name="aws-properties-networkfirewall-firewall-subnetmapping-syntax"></a>

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

### JSON
<a name="aws-properties-networkfirewall-firewall-subnetmapping-syntax.json"></a>

```
{
  "[IPAddressType](#cfn-networkfirewall-firewall-subnetmapping-ipaddresstype)" : String,
  "[SubnetId](#cfn-networkfirewall-firewall-subnetmapping-subnetid)" : String
}
```

### YAML
<a name="aws-properties-networkfirewall-firewall-subnetmapping-syntax.yaml"></a>

```
  [IPAddressType](#cfn-networkfirewall-firewall-subnetmapping-ipaddresstype): String
  [SubnetId](#cfn-networkfirewall-firewall-subnetmapping-subnetid): String
```

## Properties
<a name="aws-properties-networkfirewall-firewall-subnetmapping-properties"></a>

`IPAddressType`  <a name="cfn-networkfirewall-firewall-subnetmapping-ipaddresstype"></a>
The subnet's IP address type. You can't change the IP address type after you create the subnet.  
*Required*: No  
*Type*: String  
*Allowed values*: `DUALSTACK | IPV4 | IPV6`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`SubnetId`  <a name="cfn-networkfirewall-firewall-subnetmapping-subnetid"></a>
The unique identifier for the subnet.   
*Required*: Yes  
*Type*: String  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)