VBoxSDL is a simple graphical user interface (GUI) that lacks the nice point-and-click support which VirtualBox, our main GUI, provides. VBoxSDL is currently primarily used internally for debugging VirtualBox and therefore not officially supported. Still, you may find it useful for environments where the virtual machines are not necessarily controlled by the same person that uses the virtual machine.

As you can see in the following screenshot, VBoxSDL does indeed only provide a simple window that contains only the "pure" virtual machine, without menus or other controls to click upon and no additional indicators of virtual machine activity:

To start a virtual machine with VBoxSDL instead of the VirtualBox GUI, enter the following on a command line:

VBoxSDL --startvm <vm>

where <vm> is, as usual with VirtualBox command line parameters, the name or UUID of an existing virtual machine.

When running guest operating systems in full screen mode, the guest operating system usually has control over the whole screen. This could present a security risk as the guest operating system might fool the user into thinking that it is either a different system (which might have a higher security level) or it might present messages on the screen that appear to stem from the host operating system.

In order to protect the user against the above mentioned security risks, the secure labeling feature has been developed. Secure labeling is currently available only for VBoxSDL. When enabled, a portion of the display area is reserved for a label in which a user defined message is displayed. The label height in set to 20 pixels in VBoxSDL. The label font color and background color can be optionally set as hexadecimal RGB color values. The following syntax is used to enable secure labeling:

VBoxSDL --startvm "VM name"
      --securelabel --seclabelfnt ~/fonts/arial.ttf
      --seclabelsiz 14 --seclabelfgcol 00FF00 --seclabelbgcol 00FFFF

In addition to enabling secure labeling, a TrueType font has to be supplied. To use another font size than 12 point use the parameter --seclabelsiz.

The label text can be set with

VBoxManage setextradata "VM name" "VBoxSDL/SecureLabel" "The Label"

Changing this label will take effect immediately.

Typically, full screen resolutions are limited to certain "standard" geometries such as 1024 x 768. Increasing this by twenty lines is not usually feasible, so in most cases, VBoxSDL will chose the next higher resolution, e.g. 1280 x 1024 and the guest's screen will not cover the whole display surface. If VBoxSDL is unable to choose a higher resolution, the secure label will be painted on top of the guest's screen surface. In order to address the problem of the bottom part of the guest screen being hidden, VBoxSDL can provide custom video modes to the guest that are reduced by the height of the label. For Windows guests and recent Solaris and Linux guests, the VirtualBox Guest Additions automatically provide the reduced video modes. Additionally, the VESA BIOS has been adjusted to duplicate its standard mode table with adjusted resolutions. The adjusted mode IDs can be calculated using the following formula:

reduced_modeid = modeid + 0x30

For example, in order to start Linux with 1024 x 748 x 16, the standard mode 0x117 (1024 x 768 x 16) is used as a base. The Linux video mode kernel parameter can then be calculated using:

vga = 0x200 | 0x117 + 0x30
vga = 839

The reason for duplicating the standard modes instead of only supplying the adjusted modes is that most guest operating systems require the standard VESA modes to be fixed and refuse to start with different modes.

When using the X.org VESA driver, custom modelines have to be calculated and added to the configuration (usually in /etc/X11/xorg.conf. A handy tool to determine modeline entries can be found at http://www.tkk.fi/Misc/Electronics/faq/vga2rgb/calc.html.)

When switching from a X virtual terminal (VT) to another VT using Ctrl-Alt-Fx while the VBoxSDL window has the input focus, the guest will receive Ctrl and Alt keypress events without receiving the corresponding key release events. This is an architectural limitation of Linux. In order to reset the modifier keys, it is possible to send SIGUSR1 to the VBoxSDL main thread (first entry in the ps list). For example, when switching away to another VT and saving the virtual machine from this terminal, the following sequence can be used to make sure the VM is not saved with stuck modifiers:

kill -usr1 <pid>
VBoxManage controlvm "Windows 2000" savestate

Since Windows NT, Windows has provided a modular system logon subsystem ("Winlogon") which can be customized and extended by means of so-called GINA modules (Graphical Identification and Authentication). With Windows Vista and Windows 7, the GINA modules were replaced with a new mechanism called "credential providers". The VirtualBox Guest Additions for Windows come with both, a GINA and a credential provider module, and therefore enable any Windows guest to perform automated logons.

To activate the VirtualBox GINA or credential provider module, install the Guest Additions with using the command line switch /with_autologon. All the following manual steps required for installing these modules will be then done by the installer.

To manually install the VirtualBox GINA module, extract the Guest Additions (see the section called “Manual file extraction”) and copy the file VBoxGINA.dll to the Windows SYSTEM32 directory. Then, in the registry, create the following key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\GinaDLL

with a value of VBoxGINA.dll.

To manually install the VirtualBox credential provider module, extract the Guest Additions (see the section called “Manual file extraction”) and copy the file VBoxCredProv.dll to the Windows SYSTEM32 directory. Then, in the registry, create the following keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\
           Authentication\Credential Providers\{275D3BCC-22BB-4948-A7F6-3A3054EBA92B}

HKEY_CLASSES_ROOT\CLSID\{275D3BCC-22BB-4948-A7F6-3A3054EBA92B}

HKEY_CLASSES_ROOT\CLSID\{275D3BCC-22BB-4948-A7F6-3A3054EBA92B}\InprocServer32

with all default values (the key named (Default) in each key) set to VBoxCredProv. After that a new string named

HKEY_CLASSES_ROOT\CLSID\{275D3BCC-22BB-4948-A7F6-3A3054EBA92B}\InprocServer32\ThreadingModel

with a value of Apartment has to be created.

To set credentials, use the following command on a running VM:

VBoxManage controlvm "Windows XP" setcredentials "John Doe" "secretpassword" "DOMTEST"

While the VM is running, the credentials can be queried by the VirtualBox logon modules (GINA or credential provider) using the VirtualBox Guest Additions device driver. When Windows is in "logged out" mode, the logon modules will constantly poll for credentials and if they are present, a logon will be attempted. After retrieving the credentials, the logon modules will erase them so that the above command will have to be repeated for subsequent logons.

For security reasons, credentials are not stored in any persistent manner and will be lost when the VM is reset. Also, the credentials are "write-only", i.e. there is no way to retrieve the credentials from the host side. Credentials can be reset from the host side by setting empty values.

Depending on the particular variant of the Windows guest, the following restrictions apply:

The following command forces VirtualBox to keep the credentials after they were read by the guest and on VM reset:

VBoxManage setextradata "Windows XP" VBoxInternal/Devices/VMMDev/0/Config/KeepCredentials 1

Note that this is a potential security risk as a malicious application running on the guest could request this information using the proper interface.

Starting with version 3.2, VirtualBox provides a custom PAM module (Pluggable Authentication Module) which can be used to perform automated guest logons on platforms which support this framework. Virtually all modern Linux/Unix distributions rely on PAM.

For automated logons on Ubuntu (or Ubuntu-derived) distributions using LightDM as the display manager, please see the section called “VirtualBox Greeter for Ubuntu / LightDM”.

The pam_vbox.so module itself does not do an actual verification of the credentials passed to the guest OS; instead it relies on other modules such as pam_unix.so or pam_unix2.so down in the PAM stack to do the actual validation using the credentials retrieved by pam_vbox.so. Therefore pam_vbox.so has to be on top of the authentication PAM service list.

The pam_vbox.so module is shipped as part of the Guest Additions but it is not installed and/or activated on the guest OS by default. In order to install it, it has to be copied from /opt/VBoxGuestAdditions-<version>/lib/VBoxGuestAdditions/ to the security modules directory, usually /lib/security/ on 32-bit guest Linuxes or /lib64/security/ on 64-bit ones. Please refer to your guest OS documentation for the correct PAM module directory.

For example, to use pam_vbox.so with a Ubuntu Linux guest OS and GDM (the GNOME Desktop Manager) to logon users automatically with the credentials passed by the host, the guest OS has to be configured like the following:

To make deployment easier, you can pass the argument debug right after the pam_vbox.so statement. Debug log output will then be recorded using syslog.

Starting with VirtualBox 4.1.4 pam_vbox supports various guest property parameters which all reside in /VirtualBox/GuestAdd/PAM/. These parameters allow pam_vbox to wait for credentials to be provided by the host and optionally can show a message while waiting for those. The following guest properties can be set:

To customize pam_vbox further there are the following guest properties:

        # ./VBoxLinuxAdditions.run -- --with-autologon

        [SeatDefaults]
        greeter-session=vbox-greeter

Beginning with Windows NT 4.0, Microsoft offers a "system preparation" tool (in short: Sysprep) to prepare a Windows system for deployment or redistribution. Whereas Windows 2000 and XP ship with Sysprep on the installation medium, the tool also is available for download on the Microsoft web site. In a standard installation of Windows Vista and 7, Sysprep is already included. Sysprep mainly consists of an executable called sysprep.exe which is invoked by the user to put the Windows installation into preparation mode.

Starting with VirtualBox 3.2.2, the Guest Additions offer a way to launch a system preparation on the guest operating system in an automated way, controlled from the host system. To achieve that, see the section called “Guest control” for using the feature with the special identifier sysprep as the program to execute, along with the user name sysprep and password sysprep for the credentials. Sysprep then gets launched with the required system rights.

The VirtualBox Guest Additions contain several different drivers. If for any reason you do not wish to set them all up, you can install the Guest Additions using the following command:

  sh ./VBoxLinuxAdditions.run no_setup

After this, you will need to at least compile the kernel modules by running the command

  /usr/lib/VBoxGuestAdditions/vboxadd setup

as root (you will need to replace lib by lib64 on some 64bit guests), and on older guests without the udev service you will need to add the vboxadd service to the default runlevel to ensure that the modules get loaded.

To setup the time synchronization service, run the command

  /usr/lib/VBoxGuestAdditions/vboxadd-service setup

and add the service vboxadd-service to the default runlevel. To set up the X11 and OpenGL part of the Guest Additions, run the command

  /usr/lib/VBoxGuestAdditions/vboxadd-x11 setup

(you do not need to enable any services for this).

To recompile the guest kernel modules, use this command:

  /usr/lib/VBoxGuestAdditions/vboxadd setup

After compilation you should reboot your guest to ensure that the new modules are actually used.

This section assumes that you are familiar with configuring the X.Org server using xorg.conf and optionally the newer mechanisms using hal or udev and xorg.conf.d. If not you can learn about them by studying the documentation which comes with X.Org.

The VirtualBox Guest Additions come with drivers for X.Org versions

By default these drivers can be found in the directory

/opt/VBoxGuestAdditions-<version>/lib/VBoxGuestAdditions

and the correct versions for the X server are symbolically linked into the X.Org driver directories.

For graphics integration to work correctly, the X server must load the vboxvideo driver (many recent X server versions look for it automatically if they see that they are running in VirtualBox) and for an optimal user experience the guest kernel drivers must be loaded and the Guest Additions tool VBoxClient must be running as a client in the X session. For mouse integration to work correctly, the guest kernel drivers must be loaded and in addition, in X servers from X.Org X11R6.8 to X11R7.1 and in XFree86 version 4.3 the right vboxmouse driver must be loaded and associated with /dev/mouse or /dev/psaux; in X.Org server 1.3 or later a driver for a PS/2 mouse must be loaded and the right vboxmouse driver must be associated with /dev/vboxguest.

The VirtualBox guest graphics driver can use any graphics configuration for which the virtual resolution fits into the virtual video memory allocated to the virtual machine (minus a small amount used by the guest driver) as described in the section called “Display settings”. The driver will offer a range of standard modes at least up to the default guest resolution for all active guest monitors. In X.Org Server 1.3 and later the default mode can be changed by setting the output property VBOX_MODE to "<width>x<height>" for any guest monitor. When VBoxClient and the kernel drivers are active this is done automatically when the host requests a mode change. The driver for older versions can only receive new modes by querying the host for requests at regular intervals.

With pre-1.3 X Servers you can also add your own modes to the X server configuration file. You simply need to add them to the "Modes" list in the "Display" subsection of the "Screen" section. For example, the section shown here has a custom 2048x800 resolution mode added:

Section "Screen"
        Identifier    "Default Screen"
        Device        "VirtualBox graphics card"
        Monitor       "Generic Monitor"
        DefaultDepth  24
        SubSection "Display"
                Depth         24
                Modes         "2048x800" "800x600" "640x480"
        EndSubSection
EndSection

Apart from the standard VESA resolutions, the VirtualBox VESA BIOS allows you to add up to 16 custom video modes which will be reported to the guest operating system. When using Windows guests with the VirtualBox Guest Additions, a custom graphics driver will be used instead of the fallback VESA solution so this information does not apply.

Additional video modes can be configured for each VM using the extra data facility. The extra data key is called CustomVideoMode<x> with x being a number from 1 to 16. Please note that modes will be read from 1 until either the following number is not defined or 16 is reached. The following example adds a video mode that corresponds to the native display resolution of many notebook computers:

VBoxManage setextradata "VM name" "CustomVideoMode1" "1400x1050x16"

The VESA mode IDs for custom video modes start at 0x160. In order to use the above defined custom video mode, the following command line has be supplied to Linux:

vga = 0x200 | 0x160
vga = 864

For guest operating systems with VirtualBox Guest Additions, a custom video mode can be set using the video mode hint feature.

When guest systems with the Guest Additions installed are started using the graphical frontend (the normal VirtualBox application), they will not be allowed to use screen resolutions greater than the host's screen size unless the user manually resizes them by dragging the window, switching to full screen or seamless mode or sending a video mode hint using VBoxManage. This behavior is what most users will want, but if you have different needs, it is possible to change it by issuing one of the following commands from the command line:

VBoxManage setextradata global GUI/MaxGuestResolution any

will remove all limits on guest resolutions.

VBoxManage setextradata global GUI/MaxGuestResolution >width,height<

manually specifies a maximum resolution.

VBoxManage setextradata global GUI/MaxGuestResolution auto

restores the default settings. Note that these settings apply globally to all guest systems, not just to a single machine.

Starting with version 1.4, as an alternative to using virtual disk images (as described in detail in Chapter 5, Virtual storage), VirtualBox can also present either entire physical hard disks or selected partitions thereof as virtual disks to virtual machines.

With VirtualBox, this type of access is called "raw hard disk access"; it allows a guest operating system to access its virtual hard disk without going through the host OS file system. The actual performance difference for image files vs. raw disk varies greatly depending on the overhead of the host file system, whether dynamically growing images are used, and on host OS caching strategies. The caching indirectly also affects other aspects such as failure behavior, i.e. whether the virtual disk contains all data written before a host OS crash. Consult your host OS documentation for details on this.

Raw hard disk access -- both for entire disks and individual partitions -- is implemented as part of the VMDK image format support. As a result, you will need to create a special VMDK image file which defines where the data will be stored. After creating such a special VMDK image, you can use it like a regular virtual disk image. For example, you can use the VirtualBox Manager (the section called “The Virtual Media Manager”) or VBoxManage to assign the image to a virtual machine.

VBoxManage internalcommands createrawvmdk -filename /path/to/file.vmdk
      -rawdisk /dev/sda

VBoxManage storageattach WindowsXP --storagectl "IDE Controller"
      --port 0 --device 0 --type hdd --medium /path/to/file.vmdk

VBoxManage internalcommands createrawvmdk -filename /path/to/file.vmdk
      -rawdisk /dev/sda -partitions 1,5

VBoxManage internalcommands listpartitions -rawdisk /dev/sda

VBoxManage internalcommands createrawvmdk -filename /path/to/file.vmdk
      -rawdisk /dev/sda -partitions 1,5 -relative

VBoxManage internalcommands createrawvmdk -filename /path/to/file.vmdk
      -rawdisk /dev/sda -partitions 1,5 -mbr winxp.mbr

VirtualBox reports vendor product data for its virtual hard disks which consist of hard disk serial number, firmware revision and model number. These can be changed using the following commands:

VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/ahci/0/Config/Port0/SerialNumber" "serial"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/ahci/0/Config/Port0/FirmwareRevision" "firmware"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/ahci/0/Config/Port0/ModelNumber" "model"

The serial number is a 20 byte alphanumeric string, the firmware revision an 8 byte alphanumeric string and the model number a 40 byte alphanumeric string. Instead of "Port0" (referring to the first port), specify the desired SATA hard disk port.

The above commands apply to virtual machines with an AHCI (SATA) controller. The commands for virtual machines with an IDE controller are:

VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/piix3ide/0/Config/PrimaryMaster/SerialNumber" "serial"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/piix3ide/0/Config/PrimaryMaster/FirmwareRevision" "firmware"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/piix3ide/0/Config/PrimaryMaster/ModelNumber" "model"

For hard disks it's also possible to mark the drive as having a non-rotational medium with:

VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/ahci/0/Config/Port0/NonRotational" "1"

Additional three parameters are needed for CD/DVD drives to report the vendor product data:

VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/ahci/0/Config/Port0/ATAPIVendorId" "vendor"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/ahci/0/Config/Port0/ATAPIProductId" "product"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/ahci/0/Config/Port0/ATAPIRevision" "revision"

The vendor id is an 8 byte alphanumeric string, the product id an 16 byte alphanumeric string and the revision a 4 byte alphanumeric string. Instead of "Port0" (referring to the first port), specify the desired SATA hard disk port.

As an experimental feature, VirtualBox allows for accessing an iSCSI target running in a virtual machine which is configured for using Internal Networking mode. Please see the section called “iSCSI servers”; the section called “Internal networking”; and the section called “VBoxManage storageattach” for additional information.

The IP stack accessing Internal Networking must be configured in the virtual machine which accesses the iSCSI target. A free static IP and a MAC address not used by other virtual machines must be chosen. In the example below, adapt the name of the virtual machine, the MAC address, the IP configuration and the Internal Networking name ("MyIntNet") according to your needs. The following seven commands must first be issued:

VBoxManage setextradata "VM name" VBoxInternal/Devices/IntNetIP/0/Trusted 1
VBoxManage setextradata "VM name" VBoxInternal/Devices/IntNetIP/0/Config/MAC 08:00:27:01:02:0f
VBoxManage setextradata "VM name" VBoxInternal/Devices/IntNetIP/0/Config/IP 10.0.9.1
VBoxManage setextradata "VM name" VBoxInternal/Devices/IntNetIP/0/Config/Netmask 255.255.255.0
VBoxManage setextradata "VM name" VBoxInternal/Devices/IntNetIP/0/LUN#0/Driver IntNet
VBoxManage setextradata "VM name" VBoxInternal/Devices/IntNetIP/0/LUN#0/Config/Network MyIntNet
VBoxManage setextradata "VM name" VBoxInternal/Devices/IntNetIP/0/LUN#0/Config/IsService 1

Finally the iSCSI disk must be attached with the --intnet option to tell the iSCSI initiator to use internal networking:

VBoxManage storageattach ... --medium iscsi
         --server 10.0.9.30 --target iqn.2008-12.com.sun:sampletarget --intnet

Compared to a "regular" iSCSI setup, IP address of the target must be specified as a numeric IP address, as there is no DNS resolver for internal networking.

The virtual machine with the iSCSI target should be started before the VM using it is powered on. If a virtual machine using an iSCSI disk is started without having the iSCSI target powered up, it can take up to 200 seconds to detect this situation. The VM will fail to power up.

Execute as root the prctl command as shown below for the currently running VBoxSVC process. The process ID of VBoxSVC can be obtained using the ps command.

prctl -r -n project.max-sem-ids -v 2048 <pid-of-VBoxSVC>

This will immediately increase the semaphore limit of the currently running VBoxSVC process and allow you to launch more VMs. However, this change is not persistent and will be lost when VBoxSVC terminates.

If the user running VirtualBox is root, execute the following command:

prctl -n project.max-sem-ids -v 2048 -r -i project user.root

From this point, starting new processes will have the increased limit of 2048. You may then re-login or close all VMs and restart VBoxSVC. You can check the current VBoxSVC semaphore ID limit using the following command:

prctl -n project.max-sem-ids -i process <pid-of-VBoxSVC>

If the user running VirtualBox is not root, you must add the property to the user's default project. Create the default project and set the limit by executing as root:

projadd -U <username> user.<username>
projmod -s -K "project.max-sem-ids=(priv,2048,deny)" user.<username>

Substitute "<username>" with the name of the user running VirtualBox. Then re-login as this user to be able to run more than 120 VMs.

In NAT mode, the guest network interface is assigned to the IPv4 range 10.0.x.0/24 by default where x corresponds to the instance of the NAT interface +2. So x is 2 when there is only one NAT instance active. In that case the guest is assigned to the address 10.0.2.15, the gateway is set to 10.0.2.2 and the name server can be found at 10.0.2.3.

If, for any reason, the NAT network needs to be changed, this can be achieved with the following command:

VBoxManage modifyvm "VM name" --natnet1 "192.168/16"

This command would reserve the network addresses from 192.168.0.0 to 192.168.254.254 for the first NAT network instance of "VM name". The guest IP would be assigned to 192.168.0.15 and the default gateway could be found at 192.168.0.2.

For network booting in NAT mode, by default VirtualBox uses a built-in TFTP server at the IP address 10.0.2.3. This default behavior should work fine for typical remote-booting scenarios. However, it is possible to change the boot server IP and the location of the boot image with the following commands:

VBoxManage modifyvm "VM name" --nattftpserver1 10.0.2.2
VBoxManage modifyvm "VM name" --nattftpfile1 /srv/tftp/boot/MyPXEBoot.pxe

The VirtualBox NAT stack performance is often determined by its interaction with the host's TCP/IP stack and the size of several buffers (SO_RCVBUF and SO_SNDBUF). For certain setups users might want to adjust the buffer size for a better performance. This can by achieved using the following commands (values are in kilobytes and can range from 8 to 1024):

VBoxManage modifyvm "VM name" --natsettings1 16000,128,128,0,0

This example illustrates tuning the NAT settings. The first parameter is the MTU, then the size of the socket's send buffer and the size of the socket's receive buffer, the initial size of the TCP send window, and lastly the initial size of the TCP receive window. Note that specifying zero means fallback to the default value.

Each of these buffers has a default size of 64KB and default MTU is 1500.

By default, VirtualBox's NAT engine will route TCP/IP packets through the default interface assigned by the host's TCP/IP stack. (The technical reason for this is that the NAT engine uses sockets for communication.) If, for some reason, you want to change this behavior, you can tell the NAT engine to bind to a particular IP address instead. Use the following command:

VBoxManage modifyvm "VM name" --natbindip1 "10.45.0.2"

After this, all outgoing traffic will be sent through the interface with the IP address 10.45.0.2. Please make sure that this interface is up and running prior to this assignment.

The NAT engine by default offers the same DNS servers to the guest that are configured on the host. In some scenarios, it can be desirable to hide the DNS server IPs from the guest, for example when this information can change on the host due to expiring DHCP leases. In this case, you can tell the NAT engine to act as DNS proxy using the following command:

VBoxManage modifyvm "VM name" --natdnsproxy1 on

For resolving network names, the DHCP server of the NAT engine offers a list of registered DNS servers of the host. If for some reason you need to hide this DNS server list and use the host's resolver settings, thereby forcing the VirtualBox NAT engine to intercept DNS requests and forward them to host's resolver, use the following command:

VBoxManage modifyvm "VM name" --natdnshostresolver1 on

Note that this setting is similar to the DNS proxy mode, however whereas the proxy mode just forwards DNS requests to the appropriate servers, the resolver mode will interpret the DNS requests and use the host's DNS API to query the information and return it to the guest.

VBoxManage setextradata "VM name" \
      "VBoxInternal/Devices/{pcnet,e1000}/0/LUN#0/Config/HostResolverMappings/ \
      <uniq name of interception rule>/HostIP" <IPv4>
VBoxManage setextradata "VM name" \
      "VBoxInternal/Devices/{pcnet,e1000}/0/LUN#0/Config/HostResolverMappings/ \
      <uniq name of interception rule>/HostName" <name of host>

VBoxManage setextradata "VM name" \
      "VBoxInternal/Devices/{pcnet,e1000}/0/LUN#0/Config/HostResolverMappings/ \
      <uniq name of interception rule>/HostIP" <IPv4>
VBoxManage setextradata "VM name" \
      "VBoxInternal/Devices/{pcnet,e1000}/0/LUN#0/Config/HostResolverMappings/ \
      <uniq name of interception rule>/HostNamePattern" <hostpattern>

VBoxManage setextradata "VM name" \
      "VBoxInternal/Devices/e1000/0/LUN#0/Config/HostResolverMappings/ \
      all_blocked_site/HostIP" 127.0.0.1
VBoxManage setextradata "VM name" \
      "VBoxInternal/Devices/e1000/0/LUN#0/Config/HostResolverMappings/ \
      all_blocked_site/HostNamePattern" "*.blocked-site.*|*.fb.org"

By default, the NAT core uses aliasing and uses random ports when generating an alias for a connection. This works well for the most protocols like SSH, FTP and so on. Though some protocols might need a more transparent behavior or may depend on the real port number the packet was sent from. It is possible to change the NAT mode via the VBoxManage frontend with the following commands:

VBoxManage modifyvm "VM name" --nataliasmode1 proxyonly

and

VBoxManage modifyvm "Linux Guest" --nataliasmode1 sameports

The first example disables aliasing and switches NAT into transparent mode, the second example enforces preserving of port values. These modes can be combined if necessary.

VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBIOSVendor"        "BIOS Vendor"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBIOSVersion"       "BIOS Version"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBIOSReleaseDate"   "BIOS Release Date"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBIOSReleaseMajor"  1
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBIOSReleaseMinor"  2
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBIOSFirmwareMajor" 3
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBIOSFirmwareMinor" 4

VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiSystemVendor"      "System Vendor"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiSystemProduct"     "System Product"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiSystemVersion"     "System Version"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiSystemSerial"      "System Serial"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiSystemSKU"         "System SKU"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiSystemFamily"      "System Family"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiSystemUuid"
                                               "9852bf98-b83c-49db-a8de-182c42c7226b"

VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBoardVendor"       "Board Vendor"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBoardProduct"      "Board Product"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBoardVersion"      "Board Version"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBoardSerial"       "Board Serial"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBoardAssetTag"     "Board Tag"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBoardLocInChass"   "Board Location"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiBoardType"         10

VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiChassisVendor"     "Chassis Vendor"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiChassisVersion"    "Chassis Version"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiChassisSerial"     "Chassis Serial"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiChassisAssetTag"   "Chassis Tag"

VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiProcManufacturer"  "GenuineIntel"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiProcVersion"       "Pentium(R) III"

VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiOEMVBoxVer"        "vboxVer_1.2.3"
VBoxManage setextradata "VM name"
      "VBoxInternal/Devices/pcbios/0/Config/DmiOEMVBoxRev"        "vboxRev_12345"

By default, VirtualBox keeps all sources of time visible to the guest synchronized to a single time source, the monotonic host time. This reflects the assumptions of many guest operating systems, which expect all time sources to reflect "wall clock" time. In special circumstances it may be useful however to make the TSC (time stamp counter) in the guest reflect the time actually spent executing the guest.

This special TSC handling mode can be enabled on a per-VM basis, and for best results must be used only in combination with hardware virtualization. To enable this mode use the following command:

VBoxManage setextradata "VM name" "VBoxInternal/TM/TSCTiedToExecution" 1

To revert to the default TSC handling mode use:

VBoxManage setextradata "VM name" "VBoxInternal/TM/TSCTiedToExecution"

Note that if you use the special TSC handling mode with a guest operating system which is very strict about the consistency of time sources you may get a warning or error message about the timing inconsistency. It may also cause clocks to become unreliable with some guest operating systems depending on how they use the TSC.

For certain purposes it can be useful to accelerate or to slow down the (virtual) guest clock. This can be achieved as follows:

VBoxManage setextradata "VM name" "VBoxInternal/TM/WarpDrivePercentage" 200

The above example will double the speed of the guest clock while

VBoxManage setextradata "VM name" "VBoxInternal/TM/WarpDrivePercentage" 50

will halve the speed of the guest clock. Note that changing the rate of the virtual clock can confuse the guest and can even lead to abnormal guest behavior. For instance, a higher clock rate means shorter timeouts for virtual devices with the result that a slightly increased response time of a virtual device due to an increased host load can cause guest failures. Note further that any time synchronization mechanism will frequently try to resynchronize the guest clock with the reference clock (which is the host clock if the VirtualBox Guest Additions are active). Therefore any time synchronization should be disabled if the rate of the guest clock is changed as described above (see the section called “Tuning the Guest Additions time synchronization parameters”).

The VirtualBox Guest Additions ensure that the guest's system time is synchronized with the host time. There are several parameters which can be tuned. The parameters can be set for a specific VM using the following command:

VBoxManage guestproperty set "VM name" "/VirtualBox/GuestAdd/VBoxService/PARAMETER" VALUE

where PARAMETER is one of the following:

All these parameters can be specified as command line parameters to VBoxService as well.

Once installed and started, the VirtualBox Guest Additions will try to synchronize the guest time with the host time. This can be prevented by forbidding the guest service from reading the host clock:

VBoxManage setextradata "VM name" "VBoxInternal/Devices/VMMDev/0/Config/GetHostTimeDisabled" 1

There are several advanced customization settings for locking down the VirtualBox manager, that is, removing some features that the user should not see.

VBoxManage setextradata global GUI/Customizations OPTION[,OPTION...]

where OPTION is one of the following keywords:

To disable any GUI customization do

VBoxManage setextradata global GUI/Customizations

The following per-machine VM extradata settings can be used to change the behavior of the VM selector window in respect of certain VMs:

VBoxManage setextradata VM_NAME SETTING true

where SETTING can be:

Please note that these settings wouldn't prevent the user from reconfiguring the VM by VBoxManage modifyvm.

To disable all host key combinations, open the preferences and change the host key to None. This might be useful when using VirtualBox in a kiosk mode.

To redefine or disable certain host key actions, use the following command:

VBoxManage setextradata global GUI/Input/MachineShortcuts "FullscreenMode=F,...."

The following list shows the possible host key actions together with their default host key shortcut. Setting an action to None will disable that host key action.

To disable the fullscreen mode as well as the seamless mode, use the following command:

VBoxManage setextradata global GUI/Input/MachineShortcuts "FullscreenMode=None,SeamlessMode=None"

You can disallow certain actions when terminating a VM. To disallow specific actions, type:

VBoxManage setextradata "VM name" GUI/RestrictedCloseActions OPTION[,OPTION...]

where OPTION is one of the following keywords:

Any combination of the above is allowed. If all options are specified, the VM cannot be shut down at all.

On Linux, the web service can be automatically started during host boot by adding appropriate parameters to the file /etc/default/virtualbox. There is one mandatory parameter, VBOXWEB_USER, which must be set to the user which will later start the VMs. The paramters in the table below all start with VBOXWEB_ (VBOXWEB_HOST, VBOXWEB_PORT etc.):

Setting the parameter SSL_KEYFILE enables the SSL/TLS support. Using encryption is strongly encouraged, as otherwise everything (including passwords) is transferred in clear text.

On Solaris hosts, the VirtualBox web service daemon is integrated into the SMF framework. You can change the parameters, but don't have to if the defaults below already match your needs:

svccfg -s svc:/application/virtualbox/webservice:default setprop config/host=localhost
svccfg -s svc:/application/virtualbox/webservice:default setprop config/port=18083
svccfg -s svc:/application/virtualbox/webservice:default setprop config/user=root

The table in the previous section showing the parameter names and defaults also applies to Solaris. The parameter names must be changed to lowercase and a prefix of config/ has to be added, e.g. config/user or config/ssl_keyfile. If you made any change, don't forget to run the following command to put the changes into effect immediately:

svcadm refresh svc:/application/virtualbox/webservice:default

If you forget the above command then the previous settings will be used when enabling the service. Check the current property settings with:

svcprop -p config svc:/application/virtualbox/webservice:default

When everything is configured correctly you can start the VirtualBox web service with the following command:

svcadm enable svc:/application/virtualbox/webservice:default

For more information about SMF, please refer to the Solaris documentation.

On Mac OS X, launchd is used to start the VirtualBox webservice. An example configuration file can be found in $HOME/Library/LaunchAgents/org.virtualbox.vboxwebsrv.plist. It can be enabled by changing the Disabled key from true to false. To manually start the service use the following command:

launchctl load ~/Library/LaunchAgents/org.virtualbox.vboxwebsrv.plist

For additional information on how launchd services could be configured see http://developer.apple.com/mac/library/documentation/MacOSX/Conceptual/BPSystemStartup/BPSystemStartup.html.

The memory ballooning control inflates and deflates the memory balloon of VMs based on the VMs free memory and the desired maximum balloon size.

To set up the memory ballooning control the maximum ballooning size a VM can reach needs to be set. This can be specified via command line with

--balloon-max <Size in MB>

, on a per-VM basis extradata value with

VBoxManage setextradata <VM-Name> VBoxInternal2/Watchdog/BalloonCtrl/BalloonSizeMax <Size in MB>

or using a global extradata value with

VBoxManage setextradata global VBoxInternal2/Watchdog/BalloonCtrl/BalloonSizeMax <Size in MB>

Setting the ballooning increment in MB can be either done via command line with

--balloon-inc <Size in MB>

or using a global extradata value with

VBoxManage setextradata global VBoxInternal2/Watchdog/BalloonCtrl/BalloonIncrementMB <Size in MB>

Default ballooning increment is 256 MB if not specified.

Same goes with the ballooning decrement: Via command line with

--balloon-dec <Size in MB>

or using a global extradata value with

VBoxManage setextradata global VBoxInternal2/Watchdog/BalloonCtrl/BalloonDecrementMB <Size in MB>

Default ballooning decrement is 128 MB if not specified.

To define the lower limit in MB a balloon can be the command line with

--balloon-lower-limit <Size in MB>

can be used or using a global extradata value with

VBoxManage setextradata global VBoxInternal2/Watchdog/BalloonCtrl/BalloonLowerLimitMB <Size in MB>

is available. Default lower limit is 128 if not specified.

To detect whether a host is being isolated, that is, the host cannot reach the VirtualBox server instance anymore, the host needs to set an alternating value to a global extradata value within a time period. If this value is not set within that time period a timeout occurred and the so-called host isolation response will be performed to the VMs handled. Which VMs are handled can be controlled by defining VM groups and assigning VMs to those groups. By default no groups are set, meaning that all VMs on the server will be handled when no host response is received within 30 seconds.

To set the groups handled by the host isolation detection via command line:

--apimon-groups=<string[,stringN]>

or using a global extradata value with

VBoxManage setextradata global VBoxInternal2/Watchdog/APIMonitor/Groups <string[,stringN]>

To set the host isolation timeout via command line:

--apimon-isln-timeout=<ms>

or using a global extradata value with

VBoxManage setextradata global VBoxInternal2/Watchdog/APIMonitor/IsolationTimeoutMS <ms>

To set the actual host isolation response via command line:

--apimon-isln-response=<cmd>

or using a global extradata value with

VBoxManage setextradata global VBoxInternal2/Watchdog/APIMonitor/IsolationResponse <cmd>

The following response commands are available:

For more advanced options and parameters like verbose logging check the built-in command line help accessible with --help.

On Linux, the autostart service is activated by setting two variables in /etc/default/virtualbox. The first one is VBOXAUTOSTART_DB which contains an absolute path to the autostart database directory. The directory should have write access for every user who should be able to start virtual machines automatically. Furthermore the directory should have the sticky bit set. The second variable is VBOXAUTOSTART_CONFIG which points the service to the autostart configuration file which is used during boot to determine whether to allow individual users to start a VM automatically and configure startup delays. The config file can be placed in /etc/vbox and contains several options. One is default_policy which controls whether the autostart service allows or denies to start a VM for users which are not in the exception list. The exception list starts with exception_list and contains a comma seperated list with usernames. Furthermore a separate startup delay can be configured for every user to avoid overloading the host. A sample configuration is given below:

# Default policy is to deny starting a VM, the other option is "allow".
default_policy = deny

# Bob is allowed to start virtual machines but starting them
# will be delayed for 10 seconds
bob = {
    allow = true
    startup_delay = 10
}

# Alice is not allowed to start virtual machines, useful to exclude certain users
# if the default policy is set to allow.
alice = {
    allow = false
}
      

Every user who wants to enable autostart for individual machines has to set the path to the autostart database directory with

VBoxManage setproperty autostartdbpath <Autostart directory>

On Solaris hosts, the VirtualBox autostart daemon is integrated into the SMF framework. To enable it you have to point the service to an existing configuration file which has the same format as on Linux (see the section called “Linux: starting the autostart service via init”):

svccfg -s svc:/application/virtualbox/autostart:default setprop config/config=/etc/vbox/autostart.cfg

When everything is configured correctly you can start the VirtualBox autostart service with the following command:

svcadm enable svc:/application/virtualbox/autostart:default

For more information about SMF, please refer to the Solaris documentation.

On Mac OS X, launchd is used to start the VirtualBox autostart service. An example configuration file can be found in /Applications/VirtualBox.app/Contents/MacOS/org.virtualbox.vboxautostart.plist. To enable the service copy the file to /Library/LaunchDaemons and change the Disabled key from true to false. Furthermore replace the second parameter to an existing configuration file which has the same format as on Linux (see the section called “Linux: starting the autostart service via init”). To manually start the service use the following command:

launchctl load /Library/LaunchDaemons/org.virtualbox.vboxautostart.plist

For additional information on how launchd services could be configured see http://developer.apple.com/mac/library/documentation/MacOSX/Conceptual/BPSystemStartup/BPSystemStartup.html.