How to fix my virtual switch on my Hyper-V?

Question

Hi,

I created a Hyper-V Server(2025) and created some vm servers, such as AD, DNS, DHCP... Everything seems to be fine, so i can connect to domain, i can ping from a client with static IP the servers, but somehow the DHCP isn't working. With Wireshark I see that the Ethernet adapter forwards the DHCP Discover and on vEthernet adapter I see that, the server sends an offer back but the Ethernet adapter doesn't get it. I checked every setting of my virtual switch, but I'm out of ideas... I turned every firewall off, but it didnt't help.

Thanks for the help!

Answer 1

Hi Barni,

Thanks for your post. It seems like there is some compatibilty issue for the Hyper-V virtual switch. Here are some steps and solutions that might help resolve the issue:

1. Check Hyper-V Extensible Virtual Switch:

1.1 Ensure that the "Hyper-V Extensible Virtual Switch" is enabled in the properties of your physical network adapter. If enabling it gives a pop-up that it will disable itself, this might indicate a conflict or corruption.

1.2 You can try to uncheck and then recheck this option, followed by a system reboot.

2. Disable Microsoft Azure VFP Switch Filter Extension:

If you have recently updated to Windows 11 version 22H2, the Microsoft Azure VFP Switch Filter Extension might be causing issues. Disable this extension in the Hyper-V Manager under the Virtual Switch Manager's Extensions tab.

3. Recreate the Virtual Switch:

Even though you mentioned that you have already recreated the virtual switch, it might be worth checking to ensure that the correct external network adapter has been selected.

4. Update Network Drivers:

Ensure that your network adapter drivers are up to date. Sometimes, outdated drivers can cause compatibility issues with Hyper-V.

5. Use PowerShell to Create the Switch:

You can use PowerShell to create the virtual switch, which sometimes bypasses issues encountered in the GUI. Run the following command as an administrator: Set-VMSwitch -Name "My New vSwitch" -NetAdapterName "Ethernet" -SwitchType "External"

Replace "Ethernet" with the name of your network adapter.

6. Reset Network Configuration:

6.1 Use the netcfg -d command to reset the network configuration. This can help resolve any underlying network configuration issues. Note that this will remove all network adapters and you will need to reconfigure them: netcfg -d Reboot your system after running this command.

7. Check for Conflicting Software: Ensure that no other virtualization software (like VirtualBox or VMware) is installed and conflicting with Hyper-V. Also, disable any VPN software temporarily to see if it resolves the issue.

8. Repair Windows Installation: If none of the above steps work, consider running a repair install of Windows 11. This can fix any corrupted system files that might be causing the issue.

Please feel free to reach out if you require any additional assistance. I'm here to help

Best Regards,

Ian Xue

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