Ubuntu Manpage: x0tigervncserver - start or stop a TigerVNC scraping server

Provided by: tigervnc-scraping-server_1.12.0+dfsg-4ubuntu0.22.04.1_amd64

NAME

       x0tigervncserver - start or stop a TigerVNC scraping server

SYNOPSIS

       x0tigervncserver  [:display#|-display :display#] [-rfbport rfbport#] [-localhost [yes|no]]
       [-SecurityTypes sec-types] [-PasswordFile|-rfbauth  passwd-file]  [-PlainUsers  user-list]
       [-PAMService|-pam_service  service-name]  [-X509Key  cert-key-file]  [-X509Cert cert-file]
       [-fg]           [-useold]           [-verbose]            [-dry-run]            [-Geometry
       <width>x<height>[{+,-}<xoffset>{+,-}<yoffset>]] [X0tigervnc options...]
       x0tigervncserver -kill [{:display#,:*}|-display {:display#,:*}] [-rfbport rfbport#] [-dry-
       run] [-verbose] [-clean]
       x0tigervncserver  -list  [{:display#,:*}|-display  {:display#,:*}]   [-rfbport   rfbport#]
       [-cleanstale]
       x0tigervncserver -version

DESCRIPTION

The x0tigervncserver wrapper script is used to start the X0tigervnc server that makes an X
display remotely accessible via VNC (Virtual Network Computing). Unlike Xtigervnc, this
server does not create a virtual display. Instead, it just shares an existing X server
(typically, that one connected to the physical screen). The XDamage extension will be used
if the existing X server supports it. Otherwise, X0tigervnc will fall back to polling the
screen for changes.

As usual, the VNC desktop can be connected to with the xtigervncviewer VNC viewer or any
other VNC viewer. For details, see the xtigervncviewer(1) man page or execute
"xtigervncviewer -help".

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
~/.vnc/tigervnc.conf (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 X0tigervnc 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 x0tigervncserver. In addition
to the options listed below, any unrecognized options will be passed to X0tigervnc – see
the X0tigervnc(1) man page or "X0tigervnc -help" for details.

:display#|-display :display#
Specifies the X11 display to be shared by the X0tigervnc server.

-rfbport rfbport#
Specifies the TCP port on which X0tigervnc listens for connections from viewers
(the protocol used in VNC is called RFB – "remote framebuffer"). The default is
5900 plus the display number display#.

-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, and X509Plain. Default is VncAuth if -localhost is not given and
VncAuth,TLSVnc if -localhost no is given.

-PasswordFile passwd-file | -rfbauth passwd-file
Specifies the file containing the password used to authenticate viewers for the
security types VncAuth, TLSVnc, and X509Vnc. The passwd-file is accessed each time
a connection comes in, so it can be changed on the fly via tigervncpasswd(1). The
default password file is ~/.vnc/passwd.

-PlainUsers user-list
A comma separated list of user names that are allowed to authenticate via any of
the *Plain security types (i.e., Plain, TLSPlain, etc.). Specify * to allow any
user to authenticate using this security type. Default is to only allow the user
that has started the x0tigervncserver wrapper script.

-PAMService service-name | -pam_service service-name
PAM service name to use when authenticating users using any of the *Plain security
types. 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 x0tigervncserver.

-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
/etc/tigervnc/vncserver-config-defaults, ~/.vnc/tigervnc.conf, or
/etc/tigervnc/vncserver-config-mandatory, then the x0tigervncserver wrapper script
auto generates a self signed certificate. The auto generated self signed
certificates are stored in the files ~/.vnc/host-SrvCert.pem and ~/.vnc/host-
SrvKey.pem.

-fg Runs the X0tigervnc 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>[{+,-}<xoffset>{+,-}<yoffset>]
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
argument is empty, full screen is shown to VNC clients (this is the default).

-kill [ :{display#,*} | -display :{display#,*} ] [ -rfbport rfbport# ]
This kills a TigerVNC server previously started with x0tigervncserver or
tigervncserver. It does this by killing the VNC server process, whose process ID is
stored in the file ~/.vnc/host:rfbport#.pid. If :* is given, then x0tigervncserver
tries to kill all VNC server processes with pidfiles in ~/.vnc on the local
machine. If no display number is given, then x0tigervncserver tries to kill the VNC
server process of the user on the local machine if only one such process is running
and has a pidfile in ~/.vnc.

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

-list [ :{display#,*} | -display :{display#,*} ] [ -rfbport rfbport# ]
This lists all running TigerVNC servers previously started with x0tigervncserver or
tigervncserver. Stale entries are marked with (stale) in the output.

-cleanstale
If given with -list, then stale entries – resulting from missed cleanups of
pidfiles in ~/.vnc 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 ~/.vnc directory:

~/.vnc/tigervnc.conf
The user configuration file for x0tigervncserver.

~/.vnc/passwd
The TigerVNC password file for the security types VncAuth, TLSVnc, and X509Vnc.

~/.vnc/<host>:<rfbport#>.log
The log file for the VNC server.

~/.vnc/<host>:<rfbport#>.pid
Identifies the VNC server process ID, used by the -kill option.

~/.vnc/<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
/etc/tigervnc/vncserver-config-defaults, ~/.vnc/tigervnc.conf, or
/etc/tigervnc/vncserver-config-mandatory, then the x0tigervncserver wrapper script
auto generates a self signed certificate for the -X509Cert and -X509Key options of
the VNC server. The auto generated self signed certificates 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 -X509Cert and -X509Key
options to the x0tigervncserver wrapper script or replace the auto generated files
~/.vnc/host-SrvCert.pem and ~/.vnc/host-SrvKey.pem. These files will not be
overwritten once generated by the x0tigervncserver wrapper script.

Furthermore, there are global configuration files for x0tigervncserver in the
/etc/tigervnc directory:

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

/etc/tigervnc/vncserver-config-mandatory
If this file exists and defines options to be passed to X0tigervnc, they will
override any of the same options defined in a user's tigervnc.conf 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 X0tigervnc directly to bypass any options defined in the
/etc/tigervnc/vncserver-config-mandatory configuration file.

AUTHOR