# Network Interface

Source: /azure/services/network-interface/

## Introduction

Azure Network Interface (NIC) is the interconnection between a virtual machine and a virtual network.
A NIC enables an Azure VM to communicate with the internet, Azure, and on-premises resources.
Each NIC can have one or more IP configurations, an associated subnet, optional network security group (NSG), and optional public IP address. For more information, see [Network interfaces](https://learn.microsoft.com/en-us/azure/virtual-network/virtual-network-network-interface).

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

## Getting started

This guide is designed for users new to Network Interfaces 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 and virtual network

A network interface must be associated with a subnet. Create the prerequisite resources first:

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

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

Create a virtual network for the network interfaces:

```bash
az network vnet create \
  --name vnet-nic-demo \
  --resource-group rg-nic-demo \
  --location westeurope \
  --address-prefixes 10.0.0.0/16
```

```bash title="Output"
{
  "newVNet": {
    "addressSpace": {
      "addressPrefixes": [
        "10.0.0.0/16"
      ]
    },
    "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-nic-demo/providers/Microsoft.Network/virtualNetworks/vnet-nic-demo",
    "location": "westeurope",
    "name": "vnet-nic-demo",
    "provisioningState": "Succeeded",
    "resourceGroup": "rg-nic-demo",
    "subnets": [],
    "type": "Microsoft.Network/virtualNetworks",
    ...
  }
}
```


Create a subnet within the virtual network to attach the NICs to:

```bash
az network vnet subnet create \
  --name subnet-nic \
  --resource-group rg-nic-demo \
  --vnet-name vnet-nic-demo \
  --address-prefixes 10.0.1.0/24
```

```bash title="Output"
{
  "addressPrefix": "10.0.1.0/24",
  "delegations": [],
  "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-nic-demo/providers/Microsoft.Network/virtualNetworks/vnet-nic-demo/subnets/subnet-nic",
  "name": "subnet-nic",
  "privateEndpointNetworkPolicies": "Disabled",
  "privateLinkServiceNetworkPolicies": "Enabled",
  "provisioningState": "Succeeded",
  "resourceGroup": "rg-nic-demo",
  "type": "Microsoft.Network/virtualNetworks/subnets"
...
}
```

### Create a network interface

Create a NIC attached to the subnet:

```bash
az network nic create \
  --name nic-demo \
  --resource-group rg-nic-demo \
  --location westeurope \
  --vnet-name vnet-nic-demo \
  --subnet subnet-nic
```

```bash title="Output"
{
  "NewNIC": {
    "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-nic-demo/providers/Microsoft.Network/networkInterfaces/nic-demo",
    "ipConfigurations": [
      {
        "name": "ipconfig1",
        "primary": true,
        "privateIPAddress": "10.0.1.4",
        "privateIPAddressVersion": "IPv4",
        "privateIPAllocationMethod": "Dynamic",
        "provisioningState": "Succeeded",
        "resourceGroup": "rg-nic-demo",
        "subnet": {
          "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-nic-demo/providers/Microsoft.Network/virtualNetworks/vnet-nic-demo/subnets/subnet-nic",
          "resourceGroup": "rg-nic-demo"
        },
        ...
      }
    ],
    "location": "westeurope",
    "name": "nic-demo",
    "provisioningState": "Succeeded",
    "resourceGroup": "rg-nic-demo",
    "type": "Microsoft.Network/networkInterfaces",
    ...
  }
}
```

### Create a NIC with a static private IP

Create a second network interface and assign a static private IP address from the subnet:

```bash
az network nic create \
  --name nic-static \
  --resource-group rg-nic-demo \
  --location westeurope \
  --vnet-name vnet-nic-demo \
  --subnet subnet-nic \
  --private-ip-address 10.0.1.10
```

```bash title="Output"
{
  "NewNIC": {
    "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-nic-demo/providers/Microsoft.Network/networkInterfaces/nic-static",
    "ipConfigurations": [
      {
        "name": "ipconfig1",
        "primary": true,
        "privateIPAddress": "10.0.1.10",
        "privateIPAddressVersion": "IPv4",
        "privateIPAllocationMethod": "Static",
        "provisioningState": "Succeeded",
        "subnet": {
          "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-nic-demo/providers/Microsoft.Network/virtualNetworks/vnet-nic-demo/subnets/subnet-nic",
          "resourceGroup": "rg-nic-demo"
        },
        ...
      }
    ],
    "location": "westeurope",
    "name": "nic-static",
    "provisioningState": "Succeeded",
    "resourceGroup": "rg-nic-demo",
    "type": "Microsoft.Network/networkInterfaces",
    ...
  }
}
```

### Get and list network interfaces

Retrieve the details of a network interface and list all NICs in the resource group:

```bash
az network nic show \
  --name nic-demo \
  --resource-group rg-nic-demo
```

```bash title="Output"
{
  "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-nic-demo/providers/Microsoft.Network/networkInterfaces/nic-demo",
  "ipConfigurations": [
    {
      "name": "ipconfig1",
      "primary": true,
      "privateIPAddress": "10.0.1.4",
      "privateIPAddressVersion": "IPv4",
      "privateIPAllocationMethod": "Dynamic",
      "provisioningState": "Succeeded",
      "subnet": {
        "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-nic-demo/providers/Microsoft.Network/virtualNetworks/vnet-nic-demo/subnets/subnet-nic",
        "resourceGroup": "rg-nic-demo"
      },
      ...
    }
  ],
  "location": "westeurope",
  "name": "nic-demo",
  "provisioningState": "Succeeded",
  "resourceGroup": "rg-nic-demo",
  "type": "Microsoft.Network/networkInterfaces",
  ...
}
```


Then list all network interfaces in the resource group:

```bash
az network nic list \
  --resource-group rg-nic-demo
```

```bash title="Output"
[
  {
    "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-nic-demo/providers/Microsoft.Network/networkInterfaces/nic-demo",
    "ipConfigurations": [ { "name": "ipconfig1", "privateIPAllocationMethod": "Dynamic", ... } ],
    "location": "westeurope",
    "name": "nic-demo",
    "provisioningState": "Succeeded",
    "type": "Microsoft.Network/networkInterfaces",
    ...
  },
  {
    "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-nic-demo/providers/Microsoft.Network/networkInterfaces/nic-static",
    "ipConfigurations": [ { "name": "ipconfig1", "privateIPAddress": "10.0.1.10", "privateIPAllocationMethod": "Static", ... } ],
    "location": "westeurope",
    "name": "nic-static",
    "provisioningState": "Succeeded",
    "type": "Microsoft.Network/networkInterfaces",
    ...
  }
]
```

### Delete a network interface

Delete the network interface and verify it no longer appears in the list:

```bash
az network nic delete \
  --name nic-demo \
  --resource-group rg-nic-demo
```

## Features

The Network Interface emulator supports the following features:

- **Create and manage NICs**: Full lifecycle management including create, get, update, list, and delete.
- **Dynamic IP allocation**: Automatically assigns a private IP address from the associated subnet address space.
- **Static IP configuration**: Assign a fixed private IP address from the subnet range.
- **Public IP association**: Attach a public IP address resource to a NIC IP configuration.
- **NSG association**: Associate a network security group with a NIC.
- **IP forwarding**: Configure IP forwarding on the NIC for routing scenarios.
- **Accelerated networking**: Store and return the `enableAcceleratedNetworking` flag.
- **Tags**: Apply and update resource tags.
- **Subscription-scoped listing**: List all NICs across a subscription.

## Limitations

- **No actual networking**: Network Interface is a mock implementation. State is persisted in memory and returned faithfully, but no network packets are routed through the interface.
- **No VM attachment enforcement**: Associating a NIC with a virtual machine is accepted but VM resources are not implemented.
- **No data persistence**: NIC resources are not persisted and are lost when the emulator is stopped or restarted.

## Samples

The following samples demonstrate how to use Azure Network Interfaces 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


### Network Interface API coverage

Source service: `network-interface`. 8 of 23 tracked operations are implemented.

Service documentation: /azure/services/network-interface/

| Operation | Status |
| --- | --- |
| NetworkInterfaceIpConfigurations.Get | Not implemented |
| NetworkInterfaceIpConfigurations.List | Not implemented |
| NetworkInterfaceLoadBalancers.List | Not implemented |
| NetworkInterfaceTapConfigurations.CreateOrUpdate | Not implemented |
| NetworkInterfaceTapConfigurations.Delete | Not implemented |
| NetworkInterfaceTapConfigurations.Get | Not implemented |
| NetworkInterfaceTapConfigurations.List | Not implemented |
| NetworkInterfaces.CreateOrUpdate | Implemented |
| NetworkInterfaces.Delete | Implemented |
| NetworkInterfaces.Get | Implemented |
| NetworkInterfaces.GetCloudServiceNetworkInterface | Not implemented |
| NetworkInterfaces.GetEffectiveRouteTable | Not implemented |
| NetworkInterfaces.GetVirtualMachineScaleSetIpConfiguration | Not implemented |
| NetworkInterfaces.GetVirtualMachineScaleSetNetworkInterface | Implemented |
| NetworkInterfaces.List | Implemented |
| NetworkInterfaces.ListAll | Implemented |
| NetworkInterfaces.ListCloudServiceNetworkInterfaces | Not implemented |
| NetworkInterfaces.ListCloudServiceRoleInstanceNetworkInterfaces | Not implemented |
| NetworkInterfaces.ListEffectiveNetworkSecurityGroups | Not implemented |
| NetworkInterfaces.ListVirtualMachineScaleSetIpConfigurations | Not implemented |
| NetworkInterfaces.ListVirtualMachineScaleSetNetworkInterfaces | Not implemented |
| NetworkInterfaces.ListVirtualMachineScaleSetVMNetworkInterfaces | Implemented |
| NetworkInterfaces.UpdateTags | Implemented |