Okay to create Linux VM on host w/o Internet connection/adapter?

[fleewin10]

I've been trying to install the latest version of Lubuntu on a Win10 host. I've used both the latest and next-to-latest versions of VirtualBox. The install goes smoothly initially, but at the end, the error is that Grub didn't install. The Lubuntu installer gives options to install Grub elsewhere or install later, but none of those buttons/dropboxes are actually active. This means I have to cancel the install.

Since I've tried 32-bit and 64-bit Lubuntu, have checked and unchecked EFI, have used Windows UEFI defaults as well as modifying for legacy operations, have disabled Fast Startup/Fast Boot/Secure Boot, have installed full VirtualBox and VirtualBox without networking. I've additionally enabled and disabled just about every other setting. I even removed my Logitech wireless mouse dongle because I heard that can can cause problems (with Win10 anyway). Nothing works.

I read somewhere that an Internet connection may solve the problem of the uninstallable Grub. My Win10 host is not connected to the Internet, and never will be, and the network adapters are disabled. The plan was once I created the Lubuntu VM, I would hook up Ethernet and surf on the VM, keeping the Win10 host in air-gap mode. Could the lack of an Internet connection and the disabled network adapters on the host be causing problems in the install? I can't imagine why Grub would require Internet connectivity, but I thought I'd ask.

For comparison's sake, I can run live Linux USBs on Win10 machines that have the network adapters disabled.

Thanks

[socratis]

I see no reason whatsoever to connect the host disabled network cards with the installation of a virtual boot loader in a virtual HD. None.

Delete what you've done so far. Create a new VM with the defaults, except perhaps the amount of RAM. Do not bother with EFI, disk controllers, network cards or anything else (not that it would matter). Accept the installation defaults. If it fails, either you're not doing something correctly in the setup or (I highly doubt it) the setup is flawed.

You can always try another distribution to get that parameter out of the equation...

[fleewin10]

I see no reason whatsoever to connect the host disabled network cards with the installation of a virtual boot loader in a virtual HD. None.

Thanks for confirming that.

Delete what you've done so far. Create a new VM with the defaults, except perhaps the amount of RAM. Do not bother with EFI, disk controllers, network cards or anything else (not that it would matter). Accept the installation defaults.

I've done that close to 50 times now.

You can always try another distribution to get that parameter out of the equation...

I just tried a different Ubuntu-based distro called Trisquel. It worked the first time I tried. I think it's pretty obvious at this point that the problem lies at Lubuntu's end. I'll have to file a bug report or something.

[fleewin10]

Now that I've been able to install a number of distros -- just not the Lubuntu one I started with -- I find I have no Internet access.

I searched the forum and found this:

NAT should work out of the box if your host is somehow connected to the Internet. Make sure that your host has Internet access when you boot the VM.
viewtopic.php?f=8&t=61096

Does that totally rule out the possibility of my using the Internet on the guest with a disabled network adapter on the host?

[socratis]

No, not at all. NAT does require an active Internet connection, because it uses that connection as an intermediary/translator. What you need to do is to use Bridged mode. That way your VM will look like another PC and doesn't use the NAT as a translator.

But... It uses the network card (NIC) of the host. So, how do you prevent your host from using the NIC itself? Disable everything in the NIC's properties, except the VirtualBox Bridged adapter.

Take a look at the thread Set Network Adaptor for exclusive use of Guest VM, or search for similar topics.

[fleewin10]

Excellent. Works perfectly, thanks.

To my noobish, non-tech eyes, it looks like Win10 remains unconnected to the Internet. If the guest connection gets compromised, is it, in fact, safe to assume only the guest will be compromised, not the Win10 host?

[socratis]

Unless you specifically allow access to the host (e.g. via shared folders with read-write access) I really don't think so.

[fleewin10]

Got it, thanks.