Windows 11 24H2 Hyper V VM issues with DHCP

Question

I have been using a pihole (built upon a ubuntu VM) for a while now (~4yrs I think) with very little issue, its been great, however an issue started randomly Weds 15th and I've finally figured out the issue, but have no idea on root cause

Start of the issue

I have around 23 devices on the LAN, some windows, some linux, and some IoT devices (IP camera, smart devices, TVs etc)

Starting around 11am Weds 15th, I noticed that my front door camera wasnt working, which is strange as my main PC (windows) was fine. My son then asked if the internet was down as his TV wasnt working for youtube.

What gives?

Now most of my VMs and none of the IoT devices will get an IP from the pihole - all I see is screens of:

DHCPDISCOVER(eth0) 00:60:<redacted>
DHCPOFFER(eth0) 192.168.0.19 00:60:<redacted>
DHCPDISCOVER(eth0) 38:b4:<redacted>
DHCPOFFER(eth0) 192.168.0.106 38:b4:<redacted>

etc in the pihole log.

Strangeness continues

I have a SFF PC host running W11Pro that daily handles about 5 vms (and I use it for lab/testing/dev etc) one of which being the pihole vm.

The 3 linux VMs on the same host refuse to get an IP from the pihole, but the windows VMs will....

All the physical windows PCs seem to get an IP ok (I have tested around 5 at the moment) but NONE of the IoT devices will.

I also run a pxe server (win2019) - which runs on the same host, reserved IP, and that gets an IP ok, but PXE boot will not work as any VM i attempted wont get an IP via DHCP so then wont hit the PXE server at all.

The Steps I then tried to try to work out where the failure was;

1. I moved the piholevm to another host (also windows 11 pro 24h2) and brought it up there (to check against any hardware issues on the SFF host) the issues persisted.
2. I built a actual pihole on a raspi and while DHCP then worked, the PXE server on either 24h2 host wouldn't present tftp service
3. I then rebuilt the 2nd host on a new ssd with Win 10 pro (latest 22h2) and migrated the original pihole vm to that host and that worked!
4. I then moved the PXE server VM to the same Win10 host and that fixed all the issues.

To get the network and everything back to as was, I have now rebuilt the original SFF host with Windows 11 pro 23H2, migrated all the VMs back to that and we are now back online.

The issue was WIn11 24H2 and/or something that was pushed out to 24H2 last week.

I installed 24H2 on the host in question on our around 10/10/24 and so we've had ~2 months of flawless service, so what happened last week?

I was on a chat with Microsoft on Saturday 18/1 to ask that question (Windows 11 (#7064376884)) and after an hour or so gave up with the plan to call the commercial team, but now that I'm back up and running, I don't want to waste more time on the phone going over basics and having to try to explain all this all over again.

For now I have blocked the 24H2 upgrade on the hosts, but thought I'd post here to see if there are any people out there with similar issues and/or a fix/workaround for Hyper V issues on 24H2.

Any ideas?

Answer 1

I've got exakt the same Problem in the same constellation. Do you already found a Solution for this problem?

Answer 2

Same problem for me.

Im a french IT student and we have to make a DHCP server on virtual machine with Hyper-V. Pc host was a windows 11 education 24h2, and i got on Virtual windows server 2022 with a virtual client on windows 10.

It was impossible for my DHCP server to give an adress for my client. And wiresharck show me the same problem with that infinite discover/offer/discover/offer...

At school we were 6/7 with this problem on windows 11 24h2.

The only solution i find was to install Hyper-V on windows 10 pro.

I dont know why only 6/7 students got this problem. We all have the same version and the same machine.

I can work on a windows 10 pro without problem.

GL

Answer 3

I have exakt the same Problem on Windows Server 2022 which is hosted on Hyper-V with a Windows 11 24H2 Hypervisor. They send discover/offer/discover/offer in a Loop, but no Request.

Is there any Workaround or Fix?

I don't want to Change my Hypervisor, because it is a lot of work for me.

Yours Sincerely

Answer 4

Hi Guys,

As I said in my original post, the only thing that fixed it for me is rolling back to Win 11 23h2 and blocking the 24h2 upgrade.

I've had no update from Microsoft as yet as to why this is an issue.

Regards

Answer 5

Hi everyone, if anyone finds a solution other than switching to 23H2, it would be great if they could post their solution here. The problem still exists and is really annoying.

@Microsoft please patch this bug!!!