Hyper-V VM cannot connect to Host M/C for file sharing thru Ethernet

Hi all.

I installed Insider build 27842.1000 on MS Hyper_V VM and wanted to connect to the host machine for file/folder sharing. This build could not connect to host machine. It was connecting to the internet but not to the host.

Previously, I used to connect to host by running the host machine name, something like \\Host Machine name, in Run dialog box. With this build I can't.

I checked the Ethernet adapter properties and found out that the VM IP address was not in the LAN IP address range. My LAN IP address is like 192.168.1.xxx

VM IP address is different. The following screenshot is from the VM. VM IP address is 172.25.33.12



If I change the IP address of VM to my LAN IP address range, the internet connection is lost. Previously, I could change the IP address and still keep the internet connection. But this build allows me to change IP address but at the expense of losing the internet connection.

Can anyone please explain what has changed in later builds or what I must do to connect to both the host machine for file sharing and keep the internet connection of the VM ?

By the way, if I try to troubleshoot the VM for not connecting to the host machine, I get error code: 0x80070043 Network name not found.

It looks like you’re connecting to a switch on an internal private network. See which network switch the VM is assigned to, and maybe post the properties of that switch here. If your switch is set to "Internal," you typically get addresses in the 172 range.

suatcini54 said:

Can anyone please explain what has changed in later builds or what I must do to connect to both the host machine for file sharing and keep the internet connection of the VM ?

Click to expand...

pseymour said:

See which network switch the VM is assigned to, and maybe post the properties of that switch here. If your switch is set to "Internal," you typically get addresses in the 172 range.

Click to expand...

This is deliberate. Hyper-V acts as a DHCP server with its own 172 address range. By using this address range your Hyper-V VMs are isolated from the rest of your network while still having Internet access. The only machines they can see would be other VMs and the Host machine. This protects your other PCs from potentially malicious software you may want to test in a VM.

I have two switches, The Default Switch which is an internal switch, and an external switch I created and named WiFi. If I swap from the Default Switch to my external switch, then renew the IP address I can connect a VM to my network, where it can see and connect to any of my other PCs.

pseymour said:

It looks like you’re connecting to a switch on an internal private network. See which network switch the VM is assigned to, and maybe post the properties of that switch here. If your switch is set to "Internal," you typically get addresses in the 172 range.

Click to expand...

Sorry. I think I don't have internal or external switch. I have source and target. I created another ethernet adapter (Ethernet 2) and it was also assigned similar IPv4 address.

I'm not at home anymore so I can't get the exact lingo, but every switch in Hyper-V has a type... Internal, Private, etc. In the action pane on the right side of the Hyper-V console, you should have an option to manage switches. It's maybe the third item down, somewhere in that ballpark.

Bree said:

This is deliberate. Hyper-V acts as a DHCP server with its own 172 address range. By using this address range your Hyper-V VMs are isolated from the rest of your network while still having Internet access. The only machines they can see would be other VMs and the Host machine. This protects your other PCs from potentially malicious software you may want to test in a VM.

I have two switches, The Default Switch which is an internal switch, and an external switch I created and named WiFi. If I swap from the Default Switch to my external switch, then renew the IP address I can connect a VM to my network, where it can see and connect to any of my other PCs.

View attachment 132744

Click to expand...

I had only one ethernet adapter (default switch) and I added another one upon your advice. They both have the same properties and similar IP addresses.

I still can't connect to the host machine. Maybe I should install an earlier Windows 11 build and see if I still can connect to host machine for file sharing as I did earlier.

Thanks for your responses.

Hopefully this helps. If you need further explanation regarding the different network types and how they work or any other details about this, just let us know.

suatcini54 said:

I still can't connect to the host machine.

Click to expand...

Does the account you are using in the VM have a password? Starting with 24H2 (and up to the latest Canary build) by default Windows doesn't allow you to use an insecure connection to connect to another machine. If your VM's account has no password you'll see this if you try...



In addition, if the Host machine is on 24H2 it will refuse an insecure incoming connection. To cope with this my host machine has an account with a password that I can use to connect to it, and I create a Windows Credential in the guest VM to use this account when connecting to shares on the host.

hsehestedt said:

Hopefully this helps. If you need further explanation regarding the different network types and how they work or any other details about this, just let us know.


View attachment 132767

Click to expand...

The Default Switch is an Internal switch. This give you access to the Internet and shares on the Host machine.
If you create an External switch, in addition you will be able to access any other physical PCs on your network.

Thank you all for the detailed explanations. I didn't know Windows 11 24H2 introduced some changes in how VM intereacts with host for file/folder sharing. Anyway, I had already removed hard disk in VM before your recent responses and recreated one to clean-install Windows 24 H2. If VM still can't connect to host, then I will try your suggestions to connect to host.

@hsehestedt Thank you for showing how to create an external switch using the actual ethernet adapter on the host machine. That was a real how-to.

Regards

suatcini54 said:

@hsehestedt Thank you for showing how to create an external switch using the actual ethernet adapter on the host machine. That was a real how-to.

Click to expand...

Glad to be able to help. Please do let us know if we can help further!