tigervncserver1

Usage

Overview

tigervncserver is used to start a TigerVNC (Virtual Network Computing) desktop. tigervncserver is a Perl wrapper script which simplifies the process of starting an instance of the Xtigervnc VNC server. It runs Xtigervnc with appropriate options and starts some X applications to be displayed in the TigerVNC desktop. tigervncserver can be run with no options at all. In this case it will choose the first available display number (usually :1), start Xtigervnc as that display, and run a couple of basic applications to get you started. You can also specify the display number, in which case it will use that number if it is available and exit if not, e.g.:

Moreover, a username and a hostname can be given to start the tigervncserver via SSH on the given machine under the provided user account, e.g.:

Note that this requires the same version of the tigervncserver wrapper script on the remote machine as is on the local machine.

Creating the file ~/.config/tigervnc/xstartup allows you to change the applications run at startup (but note that this will not affect an existing desktop).

System defaults for this wrapper script are found in /etc/tigervnc/vncserver-config-defaults. These defaults can be overwritten by the user defaults given in ~/.config/tigervnc/config.pl (see the tigervnc.conf(5x) man page). Next, command-line options overwrite the settings in both tigervnc configuration files. Finally, options from /etc/tigervnc/vncserver-config-mandatory have the highest priority overwriting all previous settings.

WARNING! There is nothing stopping users from constructing their own wrapper script that calls Xtigervnc directly to bypass any options defined in the /etc/tigervnc/vncserver-config-mandatory configuration file.

Options

You can get a list of options by giving -h as an option to tigervncserver. In addition to the options listed below, any unrecognized options will be passed to Xtigervnc – see the Xtigervnc(1) man page or "Xtigervnc -help" for details.

:display#

Specifies the X11 display to be created by the Xtigervnc server.

-rfbport rfbport#

Specifies the TCP port on which Xtigervnc listens for connections from viewers (the protocol used in VNC is called RFB – "remote framebuffer"). The default is 5900 plus the display number display#. To disable, specify -1.

-rfbunixpath Unix socket path

Specifies a path to be used for listening on as a Unix domain socket by the Xtigervnc server. No Unix domain socket is created if this option is not provided.

-rfbunixmode permissions

Specifies the mode of the Unix domain socket. The default is 0600.

-localhost [yes|no]

Should the TigerVNC server only listen on localhost for incoming TigerVNC connections. Useful if you use SSH and want to stop non-SSH connections from any other hosts. If the option is not specified, then the behavior is as follows: We will only listen on localhost if the sec-types list does not contain any TLS* or X509* security types or if the list contains at least one *None security type. Otherwise, we will listen on all network addresses of the machine.

-SecurityTypes sec-types

Specify which security scheme to use for incoming connections. Valid values are a comma-separated list of None, VncAuth, Plain, TLSNone, TLSVnc, TLSPlain, X509None, X509Vnc, X509Plain, RA2, RA2ne, RA2_256, and RA2ne_256. Default is VncAuth if -localhost is not given and VncAuth,TLSVnc if -localhost no is given.

-RequireUsername [yes|no]

Specifies for the RSA-AES security types (i.e., RA2, RA2ne, RA2_256, and RA2ne_256) if authentication should be performed via Unix username and password (-RequireUsername yes) or the VNC password file (-RequireUsername no). The default is to perform authentication via the VNC password file.

-PasswordFile passwd-file | -rfbauth passwd-file

Specifies the file containing the password used to authenticate viewers for the security types VncAuth, TLSVnc, X509Vnc, RA2, RA2ne, RA2_256, and RA2ne_256. The default password file is ~/.config/tigervnc/passwd. For the RSA-AES security types, authentication via the VNC password file is only performed in case -RequireUsername is no, which is the default.

-PlainUsers user-list

Specifies a comma-separated list of user names that are allowed to authenticate via any of the *Plain security types (Plain, TLSPlain, etc.) or the RSA-AES security types (RA2, RA2ne, etc.) in case -RequireUsername is yes. Specify * to allow any user to authenticate using these security types. The default only allows the user who has started the tigervncserver wrapper script.

-PAMService service-name | -pam_service service-name

Specifies the PAM service name to use when authenticating users using any of the *Plain security types or the RSA-AES security types in case -RequireUsername is yes. Default is vnc if /etc/pam.d/vnc is present and tigervnc otherwise. The tigervnc-common package ships the /etc/pam.d/tigervnc PAM service configuration for use by tigervncserver.

-X509Cert cert-path and -X509Key key-path

Path to a X509 certificate in PEM format to be used for all X509 based security types (i.e., X509None, X509Vnc, etc.) as well as its private key also in PEM format. If the certificate and its key are not provided via the -X509Cert and -X509Key command-line options or their corresponding configuration parameters in the configuration files /etc/tigervnc/vncserver-config-defaults, ~/.config/tigervnc/config.pl, or /etc/tigervnc/vncserver-config-mandatory, then the tigervncserver wrapper script auto-generates a self-signed certificate. The auto-generated self-signed certificate and its private key are stored in the files ~/.config/tigervnc/host-SrvCert.pem and ~/.config/tigervnc/host-SrvKey.pem.

-RSAKey rsa-key-path

Path to an RSA key in PEM format used by all RSA-AES security types. If the RSA key is not provided via the -RSAKey command-line option or the corresponding configuration parameter in the configuration files /etc/tigervnc/vncserver-config-defaults, ~/.config/tigervnc/config.pl, or /etc/tigervnc/vncserver-config-mandatory, then the tigervncserver wrapper script auto-generates an RSA key. The auto-generated key is stored in the file ~/.config/tigervnc/host-SrvRsaKey.pem.

-fg

Runs the Xtigervnc server as a foreground process. Thus, the server can be aborted with CTRL-C.

-useold

Only start a new TigerVNC server if a VNC server for your account is not already running on the requested display number display# and RFB port rfbport#. If no display number is requested, a new TigerVNC server will only be started if there is no TigerVNC server running under your user account. In any case, information about the newly started TigerVNC server or the reused TigerVNC server session will be printed.

-verbose

This will turn on some debug output.

-dry-run

Do not actually do anything, but only perform the checks if the requested action would be possible. For example, there will be checks performed for the availability of the requested display number display#.

-geometry <width>x<height>

This option specifies the size of the desktop to be created. On default, a 1920x1200 desktop is created.

-wmDecoration <width>x<height>

sets the adjustment of the dimensions derived by -xdisplaydefaults 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.

-xdisplaydefaults

The -xdisplaydefaults option can be used to derive values for the above three options, i.e., -geometry to -pixelformat, from the running X session. The derived dimensions are adjusted by the -wmDecoration option.

-xstartup script

Run a custom startup script, instead of ~/.config/tigervnc/xstartup, after launching Xtigervnc. This is useful to run full-screen applications.

-noxstartup

Do not run the ~/.config/tigervnc/xstartup script after launching Xtigervnc. This option allows you to manually start a window manager in your TigerVNC session.

-desktop desktop-name

Each desktop has a name which may be displayed by the viewer. It defaults to "host:display# (username)" but you can change it with this option. It is passed in to the Xtigervnc-session script via the $VNCDESKTOP environment variable, allowing you to run a different set of applications according to the name of the desktop.

-depth depth

Specify the pixel depth in bits of the desktop to be created. Default is 24, other possible values are 16 and 32. Anything else is likely to cause strange behaviour by applications and may prevent the server from starting at all.

-pixelformat format

Specify pixel format for the 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.

-autokill [yes|no]

The -autokill option is enabled by default. If enabled, the TigerVNC server is automatically killed when the Xtigervnc-session script exits. In most cases, this has the effect of terminating Xtigervnc when the user logs out of the window manager. To disable this, use -autokill no.

-fp font-path

Specifies a font path. Otherwise, if no font path is configured, the Xtigervnc server will use its own preferred method of font handling.

-pidfile

Specifies the file that stores the pid of the Xtigervnc server to be started.

-- X session

This special 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 -- gnome would start this X session.

-kill [[user@]host][:display#|:*] [-rfbport rfbport#]

This kills a TigerVNC server previously started with tigervncserver or x0tigervncserver. It does this by killing the Xtigervnc process, whose process ID is stored in the file ~/.config/tigervnc/host:rfbport#.pid. This can be useful so you can write "tigervncserver -kill $DISPLAY", e.g., at the end of your Xtigervnc-session file after a particular application exits. If :* is given, then tigervncserver tries to kill all Xtigervnc processes with pidfiles in ~/.config/tigervnc on the local machine. If no display number is given, then tigervncserver tries to kill the Xtigervnc processes of the user on the local machine if only one such process is running and has a pidfile in ~/.config/tigervnc. If a host is specified, then tigervncserver will use SSH to kill a Xtigervnc process on the remote machine.

-clean

If given with -kill, then the logfile ~/.config/tigervnc/host:rfbport#.log is also removed.

-list [[user@]host][:display#|:*] [-rfbport rfbport#]

This lists all running TigerVNC servers previously started with tigervncserver or x0tigervncserver. If a host is specified, then tigervncserver will use SSH to list VNC desktops on the remote machine. Stale entries are marked with (stale) in the output.

-cleanstale

If given with -list, then stale entries – resulting from missed cleanups of pidfiles in ~/.config/tigervnc as well as stale X11 locks and sockets in /tmp due to Xtigervnc or X0tigervnc server crashes – are cleaned up and not shown in the output of -list.

Files

Several TigerVNC-related files are found in the ~/.config/tigervnc directory:

~/.config/tigervnc/xstartup

A shell script specifying X applications to be run when a TigerVNC desktop is started. If it doesn't exist, the system default provided in /etc/tigervnc/vncserver-config-defaults is used. A mandatory start script can also be given in /etc/tigervnc/vncserver-config-mandatory.

~/.config/tigervnc/passwd

The TigerVNC password file for the security types VncAuth, TLSVnc, and X509Vnc.

~/.config/tigervnc/<host>:<display#>.log

The log file for the VNC server and the applications started by Xtigervnc-session.

~/.config/tigervnc/<host>:<display#>.pid

Identifies the VNC server process ID, used by the -kill option.

~/.config/tigervnc/<host>-SrvCert.pem and <host>-SrvKey.pem

The security types X509None, X509Vnc, and X509Plain need a certificate and the corresponding private key. If these are not provided via the -X509Cert and -X509Key command-line options or their corresponding configuration parameters in the configuration files /etc/tigervnc/vncserver-config-defaults, ~/.config/tigervnc/config.pl, or /etc/tigervnc/vncserver-config-mandatory, then the tigervncserver wrapper script auto-generates a self-signed certificate for the -X509Cert and -X509Key options of the Xtigervnc server. The auto-generated self-signed certificate and its private key are stored in the above given two files. If the user wants their own certificate – instead of the on-demand auto-generated one – they can either specify it via the tigervncserver options -X509Cert and -X509Key or replace the files ~/.config/tigervnc/host-SrvCert.pem and ~/.config/tigervnc/host-SrvKe.pem. These files will not be overwritten once generated by the tigervncserver wrapper script.

~/.config/tigervnc/<host>-SrvRsaKey.pem

The RSA-AES security types (i.e., RA2, RA2ne, RA2_256, and RA2ne_256) need an RSA private key. If this key is not provided via the -RSAKey command-line option or the corresponding parameter in the configuration files /etc/tigervnc/vncserver-config-defaults, ~/.config/tigervnc/config.pl, or /etc/tigervnc/vncserver-config-mandatory, then the tigervncserver wrapper script auto-generates an RSA key for the -RSAKey option of the Xtigervnc server. The auto-generated key is stored in the file ~/.config/tigervnc/host-SrvRsaKey.pem.

~/.config/tigervnc/config.pl

The user configuration file for tigervncserver. To be compatible with the upstream provided wrapper scripts, we will fall back to trying to load configuration from ~/.config/tigervnc/config if ~/.config/tigervnc/config.pl is not present. Note that the config file uses key=value lines as configuration syntax, while the config.pl and the tigervncserver-config-* files in the /etc/tigervnc directory use perl(1) syntax.

Furthermore, there are global configuration files for tigervncserver in the /etc/tigervnc directory:

/etc/tigervnc/vncserver-config-defaults

The global configuration file specifying the defaults for tigervncserver.

/etc/tigervnc/vncserver-config-mandatory

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 config.pl file or ones given on the command line of this wrapper script. 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 directly to bypass any options defined in the /etc/tigervnc/vncserver-config-mandatory configuration file.