Work with a virtual network TAP using the Azure CLI

Article
02/27/2024

Important

Virtual network TAP Preview is currently on hold in all Azure regions. You can email us at azurevnettap@microsoft.com with your subscription ID and we will notify you with future updates about the preview. In the interim, you can use agent based or NVA solutions that provide TAP/Network Visibility functionality through our Packet Broker partner solutions available in Azure Marketplace Offerings.

Azure virtual network TAP (Terminal Access Point) allows you to continuously stream your virtual machine network traffic to a network packet collector or analytics tool. The collector or analytics tool is provided by a network virtual appliance partner. For a list of partner solutions that are validated to work with virtual network TAP, see partner solutions.

Create a virtual network TAP resource

Read prerequisites before you create a virtual network TAP resource. You can run the commands that follow in the Azure Cloud Shell, or by running the Azure CLI from your computer. The Azure Cloud Shell is a free interactive shell that doesn't require installing the Azure CLI on your computer. You must sign in to Azure with an account that has the appropriate permissions. This article requires the Azure CLI version 2.0.46 or later. Run az --version to find the installed version. If you need to install or upgrade, see Install Azure CLI 2.0. Virtual network TAP is currently available as an extension. To install the extension you need to run az extension add -n virtual-network-tap. If you are running the Azure CLI locally, you also need to run az login to create a connection with Azure.

Retrieve the ID of your subscription into a variable that is used in a later step:
```
subscriptionId=$(az account show \
--query id \
--out tsv)
```
Set the subscription id that you will use to create a virtual network TAP resource.
```
az account set --subscription $subscriptionId
```
Re-register the subscription ID that you'll use to create a virtual network TAP resource. If you get a registration error when you create a TAP resource, run the following command:
```
az provider register --namespace Microsoft.Network --subscription $subscriptionId
```
If the destination for the virtual network TAP is the network interface on the network virtual appliance for collector or analytics tool -
- Retrieve the IP configuration of the network virtual appliance's network interface into a variable that is used in a later step. The ID is the end point that will aggregate the TAP traffic. The following example retrieves the ID of the ipconfig1 IP configuration for a network interface named myNetworkInterface, in a resource group named myResourceGroup:
```
  IpConfigId=$(az network nic ip-config show \
  --name ipconfig1 \
  --nic-name myNetworkInterface \
  --resource-group myResourceGroup \
  --query id \
  --out tsv)
```
- Create the virtual network TAP in the westcentralus Azure region using the ID of the IP configuration as the destination. The traffic mirror destination must allow traffic to port 4789:
```
  az network vnet tap create \
  --resource-group myResourceGroup \
  --name myTap \
  --destination $IpConfigId \
  --location westcentralus
```
If the destination for the virtual network TAP is an Azure internal load balancer:
- Retrieve the front end IP configuration of the Azure internal load balancer into a variable that is used in a later step. The ID is the end point that will aggregate the TAP traffic. The following example retrieves the ID of the frontendipconfig1 front end IP configuration for a load balancer named myInternalLoadBalancer, in a resource group named myResourceGroup:
```
FrontendIpConfigId=$(az network lb frontend-ip show \
--name frontendipconfig1 \
--lb-name myInternalLoadBalancer \
--resource-group myResourceGroup \
--query id \
--out tsv)
```
- Create the virtual network TAP using the ID of the frontend IP configuration as the destination and an optional port property. The port specifies the destination port on front end IP configuration where the TAP traffic will be received :
```
az network vnet tap create \
--resource-group myResourceGroup \
--name myTap \
--destination $FrontendIpConfigId \
--port 4789 \
--location westcentralus
```

Confirm creation of the virtual network TAP:

az network vnet tap show \
--resource-group myResourceGroup
--name myTap

Add a TAP configuration to a network interface

Retrieve the ID of an existing virtual network TAP resource. The following example retrieves a virtual network TAP named myTap in a resource group named myResourceGroup:
```
tapId=$(az network vnet tap show \
--name myTap \
--resource-group myResourceGroup \
--query id \
--out tsv)
```
Create a TAP configuration on the network interface of the monitored virtual machine. The following example creates a TAP configuration for a network interface named myNetworkInterface:
```
az network nic vtap-config create \
--resource-group myResourceGroup \
--nic myNetworkInterface \
--vnet-tap $tapId \
--name mytapconfig \
--subscription subscriptionId
```

Confirm creation of the TAP configuration:

az network nic vtap-config show \
--resource-group myResourceGroup \
--nic-name myNetworkInterface \
--name mytapconfig \
--subscription subscriptionId

Delete the TAP configuration on a network interface

az network nic vtap-config delete \
--resource-group myResourceGroup \
--nic myNetworkInterface \
--name myTapConfig \
--subscription subscriptionId

List virtual network TAPs in a subscription

az network vnet tap list

Delete a virtual network TAP in a resource group

az network vnet tap delete \
--resource-group myResourceGroup \
--name myTap

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