Step 1: Disabling system-wide display access

The X server only employs its authorization protocol if all host access is disabled. Because the X server obtains a list of authorized hosts each time it starts, make sure the server provides no initial access permissions.

To disable initial host access, edit the /etc/Xn.hosts file that corresponds to your display. The /etc/Xn.hosts files determine which host machines have access to the X server, regardless of who starts the server. For example, to remove initial access permissions for local display :0, remove all host names from /etc/X0.hosts.

Make sure xhost is not executed automatically from your $HOME/.startxrc file or from a file in your $HOME/.odtpref directory.