tigervnc.conf(5x)

NAME
tigervnc.conf - configuration files for Virtual Network Computing

SYNOPSIS
$variable = "someValue"; $variable = "someValue"; $variable .= "someValue"; $variable = $var1 . $var2;

DESCRIPTION
This man page describes the syntax and options of the three configuration files loaded by tigervncserver(1), the free X server for Virtual Network Computing (VNC). These configuration files can be used to change the behavior of the server at startup time, although for all values suitable inbuilt defaults are preset. First, /etc/tigervnc/vncserver-config-defaults is read specifying the system defaults. Then, tigervncserver(1) will proceed and read $HOME/.vnc/tigervnc.conf, a file that can be changed on a per-user base. The options in this file will override the system defaults. Next, command-line options overwrite both the system defaults and the settings in $HOME/.vnc/tigervnc.conf. Finally, the configuration file /etc/tigervnc/vncserver-config-mandatory is parsed. If this file exists and defines options to be passed to Xtigervnc, they will override any of the same options defined in a user's $HOME/.vnc/tigervnc.conf as well as options given via the command line. This file offers a mechanism to establish some basic form of system-wide policy. WARNING! There is nothing stopping users from constructing their own start script that calls Xtigervnc directly to bypass any options defined in /etc/tigervnc/vncserver-config-mandatory.

EXAMPLES
The system configuration file /etc/tigervnc/vncserver-config-defaults should come with the Debian package tigervnc-standalone-server. This file serves as an example for the user file $HOME/.vnc/tigervnc.conf. The system configuration file is pretty self-descriptive, and this document will mainly repeat the information that already can be found there.

OVERVIEW
The file is in perl(1) syntax, although only variable assignment is allowed for your safety and convenience. But there still a variety of possibilities to set the string variables. All variable names are prefixed by `$'. You can assign a string to a variable using the `=' operator, and you can append a string to a variable using the `.=' operator. You can concatenate two strings using the `.' operator. You can substitute variables even inside quotes. You can access the environment variables using the notation $ENV{VARIABLE}. You can unset a variable by assigning undef to it. Use this to return the state of the variable from `set' to `use default'. You must end a line with a semicolon.

OPTIONS
The options are given with their default value if this is known.

$fontPath = "<font_dir>,<font_dir>,...";
    Should be a comma-separated list of fonts to be added to the font path. If not specified, the default will apply.

$PAMService = "tigervnc";
    This parameter specifies the PAM service utilized for Unix username and password authentication. This service is used for the *Plain security types (i.e., Plain, TLSPlain, and X509Plain) or when $RequireUsername is "yes" and any of the RSA-AES security types (i.e., RA2, RA2ne, RA2_256, and RA2ne_256) is used to establish the connection to the VNC server. If /etc/pam.d/vnc is not present, then tigervncserver(1) expects to use the tigervnc PAM service for Unix username and password authentication. Note that the tigervnc-common package provides the PAM service configuration file /etc/pam.d/tigervnc. Otherwise, if /etc/pam.d/vnc is present, the vnc PAM service will be used.

$sslAutoGenCertCommand = "openssl req
    -newkey ec:/etc/tigervnc/openssl-ecparams.pem
    -x509 -days 2190 -nodes";
    The command specified by the $sslAutoGenCertCommand parameter is used to auto-generate the certificate for the -X509Cert and -X509Key options of Xtigervnc(1). The configuration for openssl(1SSL) is taken from /etc/tigervnc/openssl.cnf where we substitute @HostName@ by the fully qualified domain name of the host.

$sslAutoGenRSAKeyCommand = "openssl genrsa
    -out RSAKeyFile 4096";
    The command specified by the $sslAutoGenRSAKeyCommand parameter is used to auto-generate an RSA key for the RSA-AES security types.

$vncUserDir = "$ENV{HOME}/.vnc";
    Contains the filename for the log files directory of Xtigervnc (the server) and the viewers that are connected to it.

$vncPasswdFile = $vncUserDir . "/passwd";
    Contains the filename of the password file for Xtigervnc. This file is only used for the security types VncAuth, TLSVnc, and X509Vnc.

$vncStartup = "/etc/X11/Xtigervnc-session";
    Points to a script that will be started at the very beginning when neither $vncUserDir/Xtigervnc-session nor $vncUserDir/xstartup is present. If $vncUserDir/Xtigervnc-session is present, it will be used. Otherwise, we try $vncUserDir/xstartup. If this is also absent, then we use the $vncStartup script. If $vncStartup is specified in $vncUserDir/tigervnc.conf, then this script is used unconditionally. That is without checking for the presence of $vncUserDir/Xtigervnc-session or $vncUserDir/xstartup.

$session = undef;
    This option can be used to control which X session type will be started. This should match one of the files in /usr/share/xsessions. For example, if there is a file called gnome.desktop, then $session = "gnome" would start this X session. The command to start the session is passed to the $vncStartup script. If this is not specified, then /etc/X11/Xtigervnc-session will start the session specified by /usr/bin/x-session-manager.

$xauthorityFile = "$ENV{HOME}/.Xauthority";
    Specifies the path to the X authority file that should be used by your Xtigervnc server.

$desktopName = "${HOSTFQDN}:nn ($ENV{LOGNAME})";
    Should be set to the default name of the desktop. This can be changed at the command line with -desktop.

$geometry = "<width>x<height>";
    This sets the framebuffer width & height to be used by the Xtigervnc server. On default, 1920x1200 is used. A values for this option as well as the $depth and $pixelformat options can be derived if the tigervncserver(1) is run in a X session – either $ENV{DISPLAY} or the session given by $getDefaultFrom – with the -xdisplaydefaults option. The geometry can also be changed at the command line with the -geometry option. Otherwise, the fixed defaults given here as well as in the following two configuration parameter documentations will be used.

$depth = "32";
    This sets the framebuffer color depth, i.e., the number of bits per pixel to use. It must be either 16, 24, or 32.

$pixelformat = "rgb888";
    Specifies the pixel format for the Xtigervnc(1) server to use (BGRnnn or RGBnnn). The default for depth 16 is RGB565 (meaning the most significant five bits represent red, the next six green, and the least significant five represent blue) and for depth 24 and 32 is RGB888.

$wmDecoration = "8x64";
    Sets the adjustment of $geometry to accommodate the window decoration used by the X11 window manager. This is used to fully display the VNC desktop even if the VNC viewer is not in full screen mode.

$getDefaultFrom
    This option lets you set the display from which you can query the default of the above three options, if you don't want to start tigervncserver from within a running X server. It will be added to the call of xdpyinfo. It is useful to get the default from the X server you will run xtigervncviewer in, because the data has not to be recalculated then. $getDefaultFrom = "-display localhost:0"; is an example how to do this.

$scrapingGeometry = "<width>x<height>+<xoffset>+<yoffset>";
    is only used by the scraping TigerVNC server. It specifies the screen area that will be shown to VNC clients, e.g., 640x480+320+240. The format is <width>x<height>+<xoffset>+<yoffset>, where `+' signs can be replaced with `-' signs to specify offsets from the right and/or from the bottom of the screen. Offsets are optional, +0+0 is assumed by default (top left corner). If the variable is not defined, full screen is shown to VNC clients (this is the default).

$localhost = "yes";
    Should the TigerVNC server only listen on localhost for incoming TigerVNC connections. This is useful if you use SSH and want to stop non-SSH connections from any other hosts. Hence, $localhost = "yes" is the default if security types are not specified. In this case, only the security type VncAuth will be offered. If the security types are specified, either via the option -SecurityTypes given to tigervncserver(1) or via the $SecurityTypes configuration parameter in /etc/tigervnc/vncserver-config-defaults or in $HOME/.vnc/tigervnc.conf, then the default depends on the specified security types. The default will be $localhost = "no" if the specified security types contain at least one of the TLS* or X509* secutity types and also contain none of the *None security types. As always, the defaults can be overwritten on the command line via the -localhost option or via the $localhost configuration parameter in /etc/tigervnc/vncserver-config-defaults or in $HOME/.vnc/tigervnc.conf.

$SecurityTypes = "VncAuth";
    The $SecurityTypes parameter contains a comma-separated list of the default security types the Xtigervnc server will offer. Available security types are None, VncAuth, Plain, TLSNone, TLSVnc, TLSPlain, X509None, X509Vnc, X509Plain, RA2, RA2ne, RA2_256, and RA2ne_256. The *None security types do not offer any kind of user authentication for connecting VNC sessions. Hence, combining a *None security type and $localhost = "no" is a very bad idea. The TLS* and X509* security types do enforce SSL encryption for data transmission. Hence, combining a TLS* or X509* security type and $localhost = "yes" is a senseless idea. Thus, in the case of $localhost = "no", the default for $SecurityTypes will be extended from VncAuth to VncAuth,TLSVnc.

$RequireUsername = "no";
    The $RequireUsername configuration parameter specifies if authentication should be performed via Unix username and password (yes) or the VNC password file (no) when utilizing one of the RSA-AES security types (i.e., RA2, RA2ne, RA2_256, or RA2ne_256).

$PlainUsers = "$ENV{LOGNAME}";
    The $PlainUsers configuration parameter contains a comma-separated list of user names that are allowed to access the VNC server via any of the *Plain security types (i.e., Plain, TLSPlain, etc.) or the RSA-AES security types in the case that $RequireUsername is "yes". Specify "*" to allow any user to authenticate using these security types. The default only allows the user who has started the VNC server. The VNC server checks the password for a user via the PAM service given by the $PAMService configuration variable or the -PAMService option.

$X509Cert and $X509Key
    These two options contain the filenames for a certificate and its key used for the security types X509None, X509Vnc, and X509Plain. If nothing is specified – the default case – then a self-signed certificate is auto-generated by tigervncserver(1) and stored in $HOME/.vnc/${HOSTFQDN}-SrvCert.pem and $HOME/.vnc/${HOSTFQDN}-SrvKey.pem, respectively. If filenames are given for $X509Cert and $X509Key either here or on the command line via -X509Cert and -X509Key options, then the auto-generation is disabled and, the user has to take care that a usable certificate is present.

$RSAKey
    This option contains the filenames for an RSA key in PEM format used by the RSA-AES security types. If nothing is specified – the default case – then an RSA key is auto-generated by tigervncserver(1) and stored in $HOME/.vnc/${HOSTFQDN}-SrvRsaKey.pem. If a filename is given for $RSAKey either here or on the command line via the -RSAKey option, then the auto-generation is disabled, and the user has to take care that a usable RSA key is present.

FILES

/etc/tigervnc/vncserver-config-defaults
    The global configuration file specifying the defaults for tigervncserver and x0tigervncserver.

~/.vnc/tigervnc.conf
    The user's tigervnc.conf configuration file. To be compatible with the upstream provided wrapper scripts, we will fall back to trying to load configuration from ~/.vnc/config if tigervnc.conf is not present. Note that ~/.vnc/config uses key=value lines as configuration syntax.

/etc/tigervnc/vncserver-config-mandatory
    If this file exists and defines options, they will override any of the same options defined in a user's tigervnc.conf file or ones given on the command line of the wrapper scripts tigervncserver and x0tigervncserver. This file offers a mechanism to establish some basic form of system-wide policy. WARNING! There is nothing stopping users from constructing their own wrapper script that calls Xtigervnc or X0tigervnc directly to bypass any options defined in the /etc/tigervnc/vncserver-config-mandatory configuration file.

SEE ALSO
tigervncconfig(1), tigervncpasswd(1), tigervncserver(1), tigervncsession(8), x0tigervncserver(1), Xtigervnc(1), X0tigervnc(1), xtigervncviewer(1)

AUTHOR
2024 - Modified for TigerVNC 1.13.1 by Joachim Falk (Joachim.Falk@gmx.de) 2022 - Modified for TigerVNC 1.12.0 by Joachim Falk (Joachim.Falk@gmx.de) 2021 - Modified for TigerVNC 1.11.0 by Joachim Falk (Joachim.Falk@gmx.de) 2016 - Modified for TigerVNC 1.7 by Joachim Falk (Joachim.Falk@gmx.de) 2006 - Modified for vnc 4.1.2 by Joachim Falk (Joachim.Falk@gmx.de) 1998 - Originally written by Marcus Brinkmann (Marcus.Brinkmann@ruhr-uni-bochum.de) for the Debian GNU/Linux Distribution.