Identify virtual NICs in Hyper-V virtual machines

• Author
• Recent Posts

Emanuel Halapciuc

Emanuel is an IT consultant who has worked for 20 years in the industry. He is currently involved in a deployment project for the European Commission and focuses on Active Directory, Group Policy, Azure, and automation with PowerShell.

Latest posts by Emanuel Halapciuc (see all)

• If a Windows service hangs, restart the service with PowerShell - Mon, Dec 12 2022
• Install, remove, list, and set default printer with PowerShell - Mon, Nov 7 2022
• Format time and date output of PowerShell New-TimeSpan - Wed, Nov 2 2022

Prerequisites

• Basic knowledge of Hyper-V and Windows Networking
• The Hyper-V module for Windows PowerShell
• Any supported version of the Windows Operating System

Current scenario (example)

If you have a VM with multiple virtual network interface cards (NIC), it can be challenging to know which NIC is connected to which virtual switch. If you created the VM using the default naming convention, they are all named "Network Adapter" in Hyper-V.

In the examples I provide below, I worked with a VM, named "Proxy2," that has two NICs: one connected to the virtual switch ExternalLan and one connected to the virtual switch Private.

NIC summary host GUI

The PowerShell equivalent to see the NIC-related summary is:

Get-VMNetworkAdapter -VMName "Proxy2" | Select-Object VMName,SwitchName,Name 

Both NICs have the same name (Network Adapter), as shown in the screenshot below.

NIC summary host PowerShell

If we look at the NICs from inside the VMs in the Network Connections applet (ncpa.cpl), there's not too much information there either. The first NIC is named "Ethernet," and all other NICs are named "Ethernet," followed by a number ("Ethernet 2," in this case).

NIC summary Guest GUI

Using PowerShell inside the VM shows the same (little) information:

Get-NetAdapter 

NIC summary Guest PS

With only this information, it is difficult to know whether, for example, the interface "Ethernet 2" is connected to the Private virtual switch or to the ExternalLan. Fortunately, there is a simple solution.

Desired scenario: VMs with NIC names that are easily identifiable

There are three simple steps to follow to make your VM's NICs easy to identify. Here is an overview, before we discuss each step in more detail.

Turn on Device Naming for the NIC, which enables seeing the name of the NIC inside the VM. This only works for supported operating systems. I hope that in the future all the operating systems supported by Hyper-V will support this, and the setting will be turned on by default. But for now, at least, this feature works on all the supported editions of Windows (both Client and Server).

On the Hyper-V host, change the name each of the VM's NICs to a more relevant name.

In the VM, I will rename the NICs from "Ethernet x" to the name I assigned in the previous step. It is easier than it sounds, and it will be clearer once we work with an actual example.

Below, we explain each step in more detail.

Step 1: Enable Device Naming

Using the GUI

Before renaming a VM's NICs, there is one thing you need to do, which allows you to "see" the (new) name of the NIC inside the VM as well. This task is accomplished by turning on the "DeviceNaming" attribute of the NIC, using the Hyper-V GUI (or the Cluster Manager console if your VMs are clustered). To turn on Device Naming in the GUI:

1. Select the Network Adapter and click the "+" sign to expand its properties.
2. Select Advanced Features.
3. Scroll to the Enable device naming property and enable it (here you also see the explanation of this setting).
4. Click Apply to apply the setting and repeat this for all the other NICs of the VM.

Device Naming GUI

Using PowerShell

Of course, you can achieve this in PowerShell, using the DeviceNaming switch with the commands Add-VMNetworkAdapter (for a new NIC) or Set-VMNetworkAdapter (for an existing NIC). Here is how to turn on Device Naming for all the NICs of the VM "Proxy2":

Get-VMNetworkAdapter -VMName "Proxy2" |Set-VMNetworkAdapter -DeviceNaming On 

Device naming PS

That is all. Just one single line for all the NICs. Of course, you could do this for all the VMs in a single line, which can save you a lot of clicks.

Step 2: Change the name of the NICs in the Hyper-V host

In this step, you will change the name of the NICs to something more relevant than "Network Adapter."

I prefer to name each NIC according to the virtual switch the NIC is connected to. In our case, the NIC connected to the ExternalLan virtual switch will be called "ExternalLan," and the NIC connected to the Private virtual switch will be called "Private." I admit it is not the most creative solution, but it is simple to automate and better than "Network Adapter" for every NIC attached to the VM.

Of course, you may use different names that make more sense to you. For instance, you might rename the NIC connected to an "external" to "Internet" and the NIC connected to an isolated network could be called "Corporate" or "Internal." I will provide examples for both scenarios.

You can assign a different name to a NIC either when you create it and add it to a VM (Add-VMNetworkAdapter) or when you reconfigure an existing one (Set-VMNetworkAdapter).

This means you can easily perform this on your existing VMs without having to remove and then add new NICs.

Note: You need to use PowerShell to change the name of a NIC; there is no way to rename it via the GUI.

Note: If you just turned on Device Naming, you will need to reboot the VM.

Scenario 1: Rename each NIC to the name of the virtual switch it is connected to

In this case, every NIC attached to the VM will be renamed to the name of the virtual switch it is connected to. Each command has a comment to explain what the command does.

# Name of the VM for which the NICs will be renamed
$VM = "Proxy2"

# Get a list of all the switches the $VM has NICs connected to
$VmSwitches = (Get-VMNetworkAdapter -VMName $VM).SwitchName

# Rename each NIC of the VM to the name of the virtual switch it is connected to
foreach ($C in $VmSwitches) { 
  Get-VMNetworkAdapter -VMName $VM `
  | Where-Object SwitchName -EQ $C `
  | Rename-VMNetworkAdapter -NewName $C -Verbose 
} 

Scenario 1 Host rename NICs

The renamed VNICs (in the GUI):

Scenario 1 Result GUI

The renamed VNICs (in PowerShell):

Get-VMNetworkAdapter -VMName "Proxy2" | Select-Object VMName,SwitchName,Name 

Scenario 1 Result PS

Scenario 2: Rename each NIC to custom names

In this case, every NIC attached to the VM will be renamed to the name of the virtual switch it is connected to. As in Scenario 1 above, each command has a comment to explain what the command does.

# Name of the VM for which the NICs will be renamed
$VM = "Proxy2"
# Rename the NIC connected to the ExternalLan virtual switch to a custom name
Get-VMNetworkAdapter -VMName $VM `
| Where-Object SwitchName -EQ "ExternalLan" `
| Rename-VMNetworkAdapter -NewName "Internet" -Verbose

# Rename the NIC connected to the Private virtual switch to a custom name
Get-VMNetworkAdapter -VMName $VM `
| Where-Object SwitchName -EQ "Private" `
| Rename-VMNetworkAdapter -NewName "Corporate" -Verbose 

Scenario 2 Host rename NICs

The renamed VNICs:

Get-VMNetworkAdapter -VMName "Proxy2" | Select-Object VMName,SwitchName,Name

At the end of Step 2, the NICs attached to the VM have been renamed to more relevant names. In the next step, the NICs from inside the VM will be renamed to match the names we just defined.

Step 3: Change the name of the NICs inside the VM using PowerShell

So far, the NICs of our VM have been renamed with more relevant names. At this moment, the name of the NICs inside the VM are still something like (the boring) "Ethernet #xx."

Old NIC names

You still need to change the NICs' names yourself inside the VM; they did not change automatically when you renamed them in the Hyper-V host.

You could accomplish this manually, but you would have to dig through one NIC at a time in Hyper-V, disconnect it or disable it inside the VM, and see what breaks.

With PowerShell, you do it all in one step. All the NICs inside the VMs are changed to have the same names as defined in Hyper-V. It's quick and easy, without "shooting in the dark" and hoping you selected the right NIC.

To accomplish this, use the command Get-NetAdapterAdvancedProperty, which exposes a lot of advanced information about each NIC. To sift through all the relevant information, you only need to look at the property "Hyper-V Network Adapter Name", as in the example below:

Get-NetAdapterAdvancedProperty -DisplayName "Hyper-V Network Adapter Name" 

Get NetAdapterAdvancedProperty

You already see where we are going. The last step is to rename each NIC with the value from "DisplayValue." (Note: If you do not see any value, it means the NIC has not been renamed after you turned on Device Naming.)

The command below will rename the NICs.

# Virtual NICs added without the switch "DeviceNaming" set to On have no value set in DisplayValue, and will be ignored
foreach ($N in (Get-NetAdapterAdvancedProperty -DisplayName "Hyper-V Network Adapter Name" | Where-Object DisplayValue -NotLike "")) {
  $N | Rename-NetAdapter -NewName $n.DisplayValue -Verbose
} 

Renaming NICs

And that's it. Next time you check your network settings, you can easily identify which NIC is which.

Renamed NICs

Conclusion

It is good hygiene to use relevant, consistent names for your NICs inside the VMs, just like those for inside your physical machines. This is particularly helpful in the case of VMs with multiple NICs.

You may modify your deployment scripts to automatically turn on Device Naming for new VMs, and you may also apply them to existing VMs.