[vbox-dev] tracking down bug in built-in RDP server

Klaus Espenlaub klaus.espenlaub at oracle.com
Mon Feb 11 09:28:14 GMT 2013

Hi Noel,

On 07.02.2013 07:19, Noel Grandin wrote:
> Hi
> I've noticed an issue where after a while the VBox built-in Remote
> Desktop Server will stop forwarding keyboard events to the guest OS.
> How can I help track this down?

You could check if the keyboard events get passed to the VM, by using 
vboxshell.py - this needs a working python 2.x install (on the host system).

Oh, I just realized that vboxshell.py is not included in the VirtualBox 
package for Windows (the python bindings are installed if python is 
found in the path at VirtualBox package install time - if you didn't 
have python installed already, just reinstall VirtualBox).

You can fetch it from 

Anyway, after downloading you should be able to start the shell with 
"python vboxshell.py". It should print your VirtualBox version number 
and show a "vbox>" prompt. The command to perform the mentioned keyboard 
event dumping is "monitorGuestKbd <vmname> <timeout>", so if you want to 
get all keyboard events for the VM named myvm for 30 seconds you need to 
type "monitorGuestKbd 'myvm' 30". For all commands mentioned don't 
include the double quotes.

If you run into any problems with this description please provide the 
error message(s).

> Thanks, Noel Grandin
> Details
> -----------
> VBox Version: 4.2.6
> Host OS: Windows 7 64-bit, fully patched
> Guest OS: Ubuntu 12.10 64-bit
> If I stay connected from an RDP client (the Windows 7 one) for some
> hours, eventually keyboard events will stop being forwarded to the guest OS.
> Mouse events still work.

Very unusual...this hasn't been reported by customers so far, and there 
are definitely plenty of them which have also extremely long-running VMs 
(and also connections to the VRDP server lasting for weeks).

> I can still connect to the guest OS via VNC and the keyboard works.

VNC works on a higher level, and this means that X11 and the related 
event handling machinery is happy. Good to know, narrows down the 
problem space.

> Disclaimer: http://www.peralex.com/disclaimer.html

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