Issue

I was forced to switch my VBox based VM from “bridged networking” to the NAT networking. In VBox that means that from guest system I can access internet but it is by default impossible to access any network service running inside VM from outside world. Even from the host machine you cannot connect to the guest system.

Then I had to copy some file from the guest to the host. While there are such options as VBox’es shared folders or emailing files from the guest I wanted to use simple ssh or scp command line.

Investigation

At first I did a quick lookup for the port numbers used by scp and ssh. Result is port 22.

Some resources from the “External Links” below suggested to configure additional network adapter (in Host-Only networking mode) for VM then do some configuration steps in the guest. But I eventually found simpler way using port forwarding rules with NAT networking.

Solution

To configure port forwarding do the following steps:

open VM’s network settings
check that network adadpter is attached to NAT - all this solution is checked with NAT only
expand Advanced section to see Port forwarding button
click Port forwarding button then click Plus icon to add new port forwarding rule
for our ssh/scp issue we need to add rule with
- protocol: TCP
- host ip: 127.0.0.1
- host port: 2222
- guest ip: leave it blank
- guest port: 22
host ip value “127.0.0.1” only allows access from the host machine; if this property is blank it means connections from any external machine is allowed too

With above configuration I can run pscp.exe from Windows host machine this way:

pscp.exe -P 2222 igor@127.0.0.1:/home/igor/arc.tar.gz C:\Users\igor\Downloads\

-P 2222 parameter is essential here - it forces pscp to use non-standard port.

External Links

6.4. Network Address Translation Service

6.7. Host-Only Networking

VirtualBox host-only network - ssh to remote machine

How to Forward Ports to a Virtual Machine and Use It as a Server

VirtualBox lab: Port Forwarding (solution is based on this)