9 Advanced topics 3. If authentication against the shadow database using pam_unix.so or pam_unix2.so is desired, the argument try_first_pass is needed in order to pass the credentials from the VirtualBox module to the shadow database authentication module. For Ubuntu, this needs to be added to /etc/pam.d/common-auth, to the end of the line referencing pam_unix.so. This argument tells the PAM module to use credentials already present in the stack, i.e. the ones provided by the VirtualBox PAM module. Warning: An incorrectly configured PAM stack can effectively prevent you from logging into your guest system! 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. Warning: At present, the GDM display manager only retrieves credentials at startup so unless the credentials have been supplied to the guest before GDM starts, automatic logon will not work. This limitation needs to be addressed by the GDM developers or another display manager must be used. 9.3 Advanced configuration for Windows guests 9.3.1 Automated Windows system preparation 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 chapter 4.7, Guest control, page 68 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. Note: Specifying the location of “sysprep.exe” is not possible – instead the following paths are used (based on the operating system): • C:\sysprep\sysprep.exe for Windows NT 4.0, 2000 and XP • %WINDIR%\System32\Sysprep\sysprep.exe for Windows Vista, 2008 Server and 7 The Guest Additions will automatically use the appropriate path to execute the system preparation tool. 138