# Public IP Prefix

Source: /azure/services/public-ip-prefix/

## Introduction

Azure Public IP Prefix is a contiguous range of Standard SKU static public IP addresses.
When you create a public IP address from a prefix, the address is guaranteed to stay within the prefix range, making it useful for allow-listing IP ranges in external firewalls.
Public IP Prefixes are commonly used with NAT Gateway to provide predictable outbound IP addresses for entire subnets. For more information, see [Public IP address prefixes](https://learn.microsoft.com/en-us/azure/virtual-network/ip-services/public-ip-address-prefix).

LocalStack for Azure provides a local environment for building and testing applications that make use of Public IP Prefixes.
The supported APIs are available on our [API Coverage section](#api-coverage), which provides information on the extent of Public IP Prefix's integration with LocalStack.

## Getting started

This guide is designed for users new to Public IP Prefixes and assumes basic knowledge of the Azure CLI and our `lstk az` proxy.

Launch LocalStack using your preferred method. For more information, see [Introduction to LocalStack for Azure](/azure/getting-started/). Once the container is running, enable Azure CLI interception by running:

```bash
lstk az start-interception
```

This command points the `az` CLI away from the public Azure management REST API and toward the LocalStack for Azure emulator API.
To revert this configuration, run:

```bash
lstk az stop-interception
```

This reconfigures the `az` CLI to send commands to the official Azure management REST API.

### Create a resource group

Create a resource group to hold all resources created in this guide:

```bash
az group create \
  --name rg-pip-prefix-demo \
  --location westeurope
```

```bash title="Output"
{
  "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-pip-prefix-demo",
  "location": "westeurope",
  "managedBy": null,
  "name": "rg-pip-prefix-demo",
  "properties": {
    "provisioningState": "Succeeded"
  },
  "tags": null,
  "type": "Microsoft.Resources/resourceGroups"
}
```

### Create a public IP prefix

Create a /29 public IP prefix (8 IP addresses):

```bash
az network public-ip prefix create \
  --name pip-prefix-demo \
  --resource-group rg-pip-prefix-demo \
  --location westeurope \
  --length 29
```

```bash title="Output"
{
  "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-pip-prefix-demo/providers/Microsoft.Network/publicIPPrefixes/pip-prefix-demo",
  "location": "westeurope",
  "name": "pip-prefix-demo",
  "properties": {
    "ipPrefix": "20.184.13.0/29",
    "ipTags": [],
    "prefixLength": 29,
    "provisioningState": "Succeeded",
    "publicIPAddressVersion": "IPv4",
    "resourceGuid": "00000000-0000-0000-0000-000000000000"
    ...
  },
  "resourceGroup": "rg-pip-prefix-demo",
  "sku": {
    "name": "Standard",
    "tier": "Regional"
  },
  "type": "Microsoft.Network/publicIPPrefixes",
  "zones": []
  ...
}
```

### Get and list public IP prefixes

Retrieve the details of the public IP prefix and list all prefixes in the resource group:

```bash
az network public-ip prefix show \
  --name pip-prefix-demo \
  --resource-group rg-pip-prefix-demo
```

```bash title="Output"
{
  "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-pip-prefix-demo/providers/Microsoft.Network/publicIPPrefixes/pip-prefix-demo",
  "location": "westeurope",
  "name": "pip-prefix-demo",
  "properties": {
    "ipPrefix": "20.184.13.0/29",
    "ipTags": [],
    "prefixLength": 29,
    "provisioningState": "Succeeded",
    "publicIPAddressVersion": "IPv4",
    "resourceGuid": "00000000-0000-0000-0000-000000000000"
    ...
  },
  "resourceGroup": "rg-pip-prefix-demo",
  "sku": {
    "name": "Standard",
    "tier": "Regional"
  },
  "type": "Microsoft.Network/publicIPPrefixes",
  "zones": []
  ...
}
```

Then list all public IP prefixes in the resource group:

```bash
az network public-ip prefix list \
  --resource-group rg-pip-prefix-demo
```

```bash title="Output"
[
  {
    "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-pip-prefix-demo/providers/Microsoft.Network/publicIPPrefixes/pip-prefix-demo",
    "location": "westeurope",
    "name": "pip-prefix-demo",
    "properties": {
      "ipPrefix": "20.184.13.0/29",
      "ipTags": [],
      "prefixLength": 29,
      "provisioningState": "Succeeded",
      "publicIPAddressVersion": "IPv4"
    },
    "resourceGroup": "rg-pip-prefix-demo",
    "sku": { "name": "Standard", "tier": "Regional" },
    "type": "Microsoft.Network/publicIPPrefixes",
    "zones": []
  }
]
```

### Delete the public IP prefix

Delete the public IP prefix and verify it no longer appears in the list:

```bash
az network public-ip prefix delete \
  --name pip-prefix-demo \
  --resource-group rg-pip-prefix-demo
```

Then list all public IP prefixes to confirm the resource group is now empty:

```bash
az network public-ip prefix list --resource-group rg-pip-prefix-demo
```

```bash title="Output"
[]
```

## Features

The Public IP Prefix emulator supports the following features:

- **Create and manage prefixes**: Full lifecycle management including create, get, update, list, and delete.
- **Configurable prefix length**: For IPv4, set prefix length /28 through /31 to define how many addresses the range contains (/28 = 16, /29 = 8, /30 = 4, /31 = 2 addresses), matching Azure’s [published prefix sizes](https://learn.microsoft.com/en-us/azure/virtual-network/ip-services/public-ip-address-prefix#prefix-sizes). IPv6 uses /124–/127 for the same address counts when you configure an IPv6 prefix in Azure.
- **Tags**: Apply and update resource tags on public IP prefix resources.
- **Subscription-scoped listing**: List all public IP prefixes across a subscription.
- **Multiple prefix lengths**: Create prefixes of different lengths within the same resource group.

## Limitations

- **No real IP range allocation**: Public IP Prefix is a mock implementation. No actual IP address ranges are allocated from Azure's public IP pools, and no public internet connectivity is provided.
- **No IP address derivation**: Creating individual public IP addresses from a prefix is not enforced; both resources are stored independently.
- **No data persistence**: Public IP prefix resources are not persisted and are lost when the emulator is stopped or restarted.

## Samples

The following samples demonstrate how to use Azure Public IP Prefixes with LocalStack for Azure:

- [Function App and Service Bus](https://github.com/localstack/localstack-azure-samples/tree/main/samples/function-app-service-bus/dotnet/)
- [Web App and Cosmos DB for MongoDB API](https://github.com/localstack/localstack-azure-samples/tree/main/samples/web-app-cosmosdb-mongodb-api/python/)

## API Coverage


### Public IP Prefix API coverage

Source service: `public-ip-prefix`. 6 of 6 tracked operations are implemented.

Service documentation: /azure/services/public-ip-prefix/

| Operation | Status |
| --- | --- |
| PublicIpPrefixes.CreateOrUpdate | Implemented |
| PublicIpPrefixes.Delete | Implemented |
| PublicIpPrefixes.Get | Implemented |
| PublicIpPrefixes.List | Implemented |
| PublicIpPrefixes.ListAll | Implemented |
| PublicIpPrefixes.UpdateTags | Implemented |