Windows 10 V1903: IP resolution bug in Hyper-V switch

[German]In Windows 10 May 2019 Update (version 1903) and possibly also in October 2018 Update (version 1809) there is a bug in the 'Default Switch' which leads to issues with Windows Sandbox, Mobile Hotspot or with Windows Containers – they do not work. The reason for this is that the default switch probably does not get an IP address. The reason are updates from Windows 10 and from the hardware manufacturer's system updater. But there is a workaround.

First reports

Frank Lesniak posted this for the first time in the feedback hub for Windows Insiders. I myself became aware of the problem a few days ago via the following tweet. 

People on #Windows10 1903 and 1809 – please try using Hyper-V, (Windows) Mobile Hotspot, Windows Sandbox, or Windows Containers? Do they work?

I bet they don't! Or at least they don't for me. See details here & please RT/upvote if you are seeing the same: https://t.co/VgwWyDKwh9

— Frank Lesniak (@FrankLesniak) 31. Mai 2019

That was still a question from Frank at the end of May 2019. Later he came across an MSND forum post HNS failed with error : Element not found] when creating network w/ interface name specified from Rafael Rivera, that seems to address the same issue.

'm creating a transparent network device with:

docker network create -d transparent –gateway 192.168.1.1 –subnet 192.168.1.0/24 -o com.docker.network.windowsshim.networkname=external -o com.docker.network.windowsshim.interface="Virtual Machine Access" -o com.docker.network.windowsshim.dnsservers=192.168.1.1 external

The Docker daemon is returning: Error response from daemon: HNS failed with error : Element not found.

• Docker server: 17.03.1-ee-3
• Windows Server 2016 Standard w/ Hyper-V role installed
• IPv6 is up and running on all interfaces
• Interface in question is named "Virtual Machine Access" and is used by Hyper-V machines on the same machine. Not currently set up with management operating system access, though I tried with/without this set.

….

But there was no response to that question. Frank Lesniak continued testing and found the cause.

Hyper-V guests do not receive an IP address

I had the above mentioned tweet on observation. Frank Lesniak then updated his tweets a few days ago with this post.

I have figured out my issue with Hyper-V's "Default Switch" not functioning on #Win10 1903 (remember: this also caused Mobile Hotspot to not work). Symptom: #HyperV guest #VM (or connected device on Mobile Hotspot) never gets an IP address from DHCP… (1/n)

— Frank Lesniak (@FrankLesniak) 11. Juni 2019

He was able to narrow down the error. The reason for malfunctions in the Windows Container, Mobile Hotspot or Windows Sandbox area in virtual machines is a bug. The Hyper VMs are never assigned an IP address by the DHCP server.

Updates kill the feature

In further tweets he outlined this issue, which is probably related to automatic driver updates by Windows 10, further updates and the Lenovo system update program.

I can 100% reproduce this problem if I install 1903 bare-metal on any of my three systems, let Windows complete automatic driver updates, patch Windows, then run the hardware manufacturer's system update program (e.g., Lenovo Vantage). Finally, install Hyper-V… (2/n)

— Frank Lesniak (@FrankLesniak) 11. Juni 2019

In the tweet above, he states how he can reproduce this on several bare-metal systems. As soon as drivers are updated and updates are installed and the system updater of the device manufacturer is executed, there is the IP issue back.

… and then try firing up a VM (or use Mobile Hotspot). A DHCP address will never be handed out. You might also see errors in the Host-Network-Service log, event ID 1030, w/ error codes 0x80070490 / 0x80070032 and mention of IpICSHlpStopDhcpServer / IpICSHlpStopDnsServer (3/n) pic.twitter.com/8lPGA2gm56

— Frank Lesniak (@FrankLesniak) 11. Juni 2019

The VM no longer receives an IP address from the DHCP server and the event log of the host network adapter contains error 0x80070490 / 0x80070032 under event ID 1030.

Strange workaround

In another tweet Frank posted a pretty crude workaround. You should install the Windows Sandbox.

WORKAROUND: install Windows Sandbox (in addition to Hyper-V, in this case). Having Windows Sandbox installed seems to allow Windows to have what it needs to properly hand out a DHCP address.

SO GLAD TO FINALLY HAVE A WORKAROUND FOR THIS PROBLEM!

— Frank Lesniak (@FrankLesniak) 11. Juni 2019

In this case, the IP address assignment to the VM works again. I don't know if it works on a non English Windows 10 V1903. Because there is the sandbox bug (see Windows 10 V1903: Update KB4497936 breaks Sandbox). But maybe it'll help someone who's searching a branch why Hyper-V guests make trouble with Internet features.