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Comment by TicklishTiger | Hacker News Reader

I often have the problem that I am in a VirtualBox VM and want to get a file to the host.

I never found a solution other then to upload it somewhere on the internet and then download it on the host.

Yes, I know you can probably configure something before starting the VM to make VM and host share files.

But I usually want to have them completely sepereated. Only when the need arises to transfer a file, I would like to do so ad hoc.

Is there a solution?

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You can add shared folders at the host side at runtime and then mount them in the guest. Or you can expose network filesystems (CIFS, NFS) on either side and mount on the other.

As I understand it, host and guest can not see each other on the lan. So I think neither is possible.

That depends on how you configure the networking for the VM.

Yes, I stated that in my original question already.

Not clearly IMHO. If the VM being able talk to the host is not acceptable to you, even if you only activate that during runtime when you need it, then scp obviously isn't a solution.

Change the networking config from NAT to bridged. The VM will now appear as a truly independent device on your LAN, as if it were plugged into a switch.

But then it can talk to the lan. I don't want that. The whole reason I have some apps running in a VM is to be shielded from them.

Then you need to add a port forward to get through the NAT. However, NAT isn't security and you might be better off using a bridge and a firewall to shield your VM.

virtualbox adds a network interface to connect host and VM to each other, you can reach them via private IPs. the exact IPs used depend on the type of network mapping used (NAT, host-only, bridged)

If the file is saved on a kind of disk, and not only in-memory on your VM, it is already on your host in the disk image of the VM, you just extract it. With qemu I usually loopback mount in readonly mode the disk and access whatever I want from the VM guest that way.

VirtualBox creates .vdi files. Looks like there is no easy way to mount them.

If you go this way, why not simply use SCP on the host?

Where would I scp to?

SCP from Guest to Host

What is the ip of the host? I am pretty sure the guest is seeing a lan that only contains itself.

It sounds like you are talking about NAT mode on virtualbox. In this case you can set up port forwarding in the network settings. Also, you can actually reach the host from the guest. In my case my guest has an IP of 10.0.2.15 by default, and I can reach the host on 10.0.2.2

You open a shell on the host, and then `scp guest:path/to/file target/path/to/file`.

What is 'guest' here? As far as I know, the VM does not have an IP on the lan.

I mean, you need to be able to use your VM Manager tool to find out what is the IP/hostname of your guest.

A Default VirtualBox configuration does not allow direct host-> guest access, it's on some hidden VB-only NAT. You need to change the Network Interface type to Bridged or Host-only or something else to have access to the VM.

I haven't done it for some time, but in my memory it was neither a problem on OSX nor on Linux with VBox. Maybe try Vagrant? I don't remember, sorry. But ask around and you should find a super easy way to make this happen.

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