By default under Linux, VNC Server in Virtual Mode uses a version of the Xorg server built-in to Xvnc. This is old, and hard to update. On some platforms, modern desktop environments fail to load (resulting in a gray screen), and modern applications and extensions (particularly those using hardware acceleration) do not work.
From VNC Connect 6.2.0, you can configure VNC Server to utilise the latest version of the Xorg server present on your system instead. More desktop environments, applications and extensions will likely be compatible out-of-the-box, giving a much better user experience, especially on Red Hat-compatible distributions.
Note: If you are using Ubuntu, SUSE or Raspberry Pi OS (previously called Raspbian), you should continue to use Xvnc. This means that under Ubuntu and SUSE you will still need to switch desktop environment in order to avoid the grey screen. There's no issue under Raspberry Pi OS (previously called Raspbian), however, as the default PIXEL desktop environment works well with Xvnc.
Xorg and the Xorg dummy video driver must be installed. For example:
- Red Hat/CentOS 7:
yum install xorg-x11-drv-dummy
- Red Hat/CentOS 6:
yum install xorg-x11-drv-dummy xorg-x11-drv-void
apt install xserver-xorg-video-dummy
In addition, VNC Connect 6.2.0+ must be installed and licensed. Download.
Enabling the system Xorg server
To enable the system Xorg server for all users, run
vncinitconfig -enable-system-xorg as root. Run without root privileges to enable just for you.
To disable the system Xorg server and use Xvnc again, run
Configuring VNC Server
VNC Server parameters
VNC Server parameters can be specified in the following new configuration files:
/etc/vnc/config.d/vncserver-x11-virtual (for all users)
~/.vnc/config.d/vncserver-x11-virtual (just for you)
Note that the
vncinitconfig -enable-system-xorg script offers to copy over existing parameters from
~/.vnc/config.d/Xvnc respectively for you.
Note: The RandR VNC Server parameter cannot enable users to switch between available screen resolutions. See Xorg configuration, below.
Xorg server options can continue to be set in the following files:
~/.vnc/config (ignored if the -config flag is used, below)
...or in a custom file identified by the
vncserver-virtual -config FILE-PATH flag at start-up.
These options are passed directly to the system Xorg server. Consult the Xorg man page for a list of valid options; invalid options cause errors. Note that the following options supported by Xvnc are not supported:
Custom Xorg settings can be specified in the new
/etc/X11/vncserver-virtual-dummy.conf file. In particular, you can set non-standard screen resolutions by adding additional ModeLine entries to the Monitor section. A convenient way to generate the required Modeline is by using the
gtf command, e.g.
gtf 1920 1080 60
where 1920 is the width, 1080 is the height, and 60 is the refresh rate. Replace these values as required.
For larger resolutions, you may also need to change the VideoRam entry in the Device section and add a Virtual entry under the Display subsection of the Screen section; see the Xorg.conf man page for more information.
Note the VNC Server RandR parameter cannot be used to enable a connected VNC Viewer user to cycle between available screen resolutions during a remote control session. The connected user should use the standard Screen Display or Monitor app instead.
Xstartup scripts can continue to be used to specify desktop environments and applications for virtual desktops in the same way as for Xvnc.
Installing from a network share
If you're following these instructions to install VNC Server on a central computer, then perform the following operation after step 5 and before step 6:
5a) Run the command
vncinitconfig -virtual-xorg-conf as root to generate a
When using the Xfce or KDE desktop environments, some fonts may appear small, depending on the screen resolution.
- To fix this for Xfce, navigate to Applications > Settings > Appearance and enable Custom DPI setting on the Fonts tab, making sure this is set to 96.
- To fix this for KDE, navigate to System Settings > Application Appearance and enable Force fonts DPI on the Fonts tab, making sure this is set to 96.