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man pages section 1: User Commands

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Updated: Wednesday, February 10, 2021

x0vncserver (1)


x0vncserver - TigerVNC Server for X displays


x0vncserver [options]
x0vncserver -version


X0VNCSERVER(1)                  TigerVNC Manual                 X0VNCSERVER(1)

       x0vncserver - TigerVNC Server for X displays

       x0vncserver [options]
       x0vncserver -version

       x0vncserver  is  a  TigerVNC  Server which makes any X display remotely
       accessible via VNC, TigerVNC or compatible viewers.  Unlike Xvnc(1), it
       does not create a virtual display.  Instead, it just shares an existing
       X server (typically, that one connected to the physical screen).

       XDamage will be used if the existing X server  supports  it.  Otherwise
       x0vncserver will fall back to polling the screen for changes.

       x0vncserver  interprets  the  command line as a list of parameters with
       optional values.  Running x0vncserver -h will show a list of all  valid
       parameters  with  short descriptions.  All parameters are optional, but
       normally you would have to use  the  PasswordFile  parameter  (see  its
       description below).

       There  are  several  forms of specifying parameters in the command line
       (here we use `SomeParameter' as an example parameter name):

              Enable the parameter, turn the feature on.   This  form  can  be
              used with parameters that simply enable or disable some feature.

              Disable the parameter, turn the feature off.

              Assign  the  specified value to the parameter.  The leading dash
              can be omitted, or it can be doubled if desired  (like  in  GNU-
              style long options).

       Parameter  names  are case-insensitive, their order in the command line
       can be arbitrary.

              The X display name.  If not specified, it defaults to the  value
              of the DISPLAY environment variable.

              TCP  port to listen for incoming VNC connections (RFB protocol).
              The default port is 5900.

       Log    Specifies which log output should be directed  to  which  target
              logger,  and  the  level  of  output to log.  Format is log:tar-
              get:level.  Default is *:stderr:30 (log  everything  to  stderr,
              set log level to 30).  Log level should be a value between 0 and
              100, higher levels produce more output.

              This parameter allows to specify a file name with IP access con-
              trol  rules.  The file should include one rule per line, and the
              rule format is one of  the  following:  +address/prefix  (accept
              connections  from  the specified address group), -address/prefix
              (reject connections) or ?address/prefix (query the local  user).
              The  first rule matching the IP address determines the action to
              be performed.  Rules that include only an action sign (+,  -  or
              ?)  will match any IP address.  Prefix is optional and is speci-
              fied as a number of bits (e.g. /24).  Default is to accept  con-
              nections from any IP address.

              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,TLSVnc.

       rfbauth, PasswordFile
              Password file for VNC authentication.  There is no default,  you
              should  specify  the  password  file  explicitly.  Password file
              should be created with the vncpasswd(1) utility.

              Obfuscated binary encoding of the password  which  clients  must
              supply  to access the server.  Using this parameter is insecure,
              use PasswordFile parameter instead.

              A comma separated list of user names that are allowed to authen-
              ticate  via  any of the "Plain" security types (Plain, TLSPlain,
              etc.). Specify * to allow any user to  authenticate  using  this
              security type. Default is to deny all users.

       pam_service, PAMService
              PAM  service  name to use when authentication users using any of
              the "Plain" security types. Default is vnc.

              Path to a X509 certificate in PEM format to be used for all X509
              based security types (X509None, X509Vnc, etc.).

              Private  key  counter part to the certificate given in X509Cert.
              Must also be in PEM format.

              The number of unauthenticated connection attempts  allowed  from
              any  individual  host before that host is black-listed.  Default
              is 5.

              The initial timeout applied when a host is  first  black-listed.
              The  host  cannot  re-attempt  a  connection  until  the timeout
              expires.  Default is 10.

              Prompt the local user to accept or reject incoming  connections.
              Default is off.

              Number  of  seconds  to show the Accept Connection dialog before
              rejecting the connection.  Default is 10.

              Always treat incoming connections as shared, regardless  of  the
              client-specified setting.  Default is off.

              Never  treat  incoming  connections as shared, regardless of the
              client-specified setting.  Default is off.

              Disconnect existing clients if an incoming  connection  is  non-
              shared.   If combined with NeverShared then new connections will
              be refused while there is a client active.  Default is on.

              Accept key press and release events from  clients.   Default  is

              Accept pointer events from clients.  Default is on.

              Comma-separated list of incoming keysyms to remap.  Mappings are
              expressed as two hex values, prefixed by 0x, and separated by ->
              (`dash' and `greater than' characters).

              Always  use RFB protocol version 3.3 for backwards compatibility
              with badly-behaved clients.  Default is off.

              This option specifies the screen area that will be shown to  VNC
              clients.  The format is widthxheight+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).

              Maximum percentage of CPU time to be consumed when  polling  the
              screen.  Default is 35.

              Milliseconds  per  one  polling  cycle.   Actual interval may be
              dynamically  adjusted  to  satisfy  MaxProcessorUsage   setting.
              Default is 30.

              x0vncserver  uses  a  "deferred update" mechanism which enhances
              performance in many cases. After any change to the  framebuffer,
              x0vncserver  waits  for  this number of milliseconds (default 1)
              before sending an update to any waiting clients. This means that
              more  changes tend to get coalesced together in a single update.
              Setting it to 0 results in the same behaviour  as  earlier  ver-
              sions  of x0vncserver, where the first change to the framebuffer
              causes an immediate update to any waiting clients.

              Keep delaying sending the screen update to  the  client(s)  each
              time  the  screen  is  updated.  Otherwise the delay is from the
              first update. Default is off.

              Perform pixel comparison on framebuffer  to  reduce  unnecessary
              updates.  Can be either 0 (off), 1 (always) or 2 (auto). Default
              is 2.

       UseSHM Use MIT-SHM extension if available.  Using that extension accel-
              erates reading the screen.  Default is on.

              Use  overlay  mode  in  IRIX or Solaris (does not have effect in
              other systems).  This enables system-specific access to complete
              full-color  version  of  the  screen (the default X visual often
              provides 256 colors).  Also, in overlay  mode,  x0vncserver  can
              show correct mouse cursor.  Default is on.

              Zlib  compression  level  for  ZRLE encoding (it does not affect
              Tight  encoding).   Acceptable  values  are  between  0  and  9.
              Default is to use the standard compression level provided by the
              zlib(3) compression library.

              Use improved compression algorithm for  Hextile  encoding  which
              achieves better compression ratios by the cost of using slightly
              more CPU time.  Default is on.

              The number of seconds after which an idle VNC connection will be
              dropped (zero means no timeout).  Default is 0.

              Terminate  when  no  client  has  been  connected for N seconds.
              Default is 0.

              Terminate when a  client  has  been  connected  for  N  seconds.
              Default is 0.

              Terminate after N seconds of user inactivity.  Default is 0.

              The  number  of  milliseconds  to  wait for a client which is no
              longer responding.  Default is 20000.

              Currently unused.

       See attributes(7) for descriptions of the following attributes:

       |Availability   | x11/server/xvnc  |
       |Stability      | Volatile         |
       Xvnc(1), vncpasswd(1),

       Constantin Kaplinsky and others.

       VNC was originally developed by the  RealVNC  team  while  at  Olivetti
       Research  Ltd  /  AT&T Laboratories Cambridge.  TightVNC additions were
       implemented by Constantin Kaplinsky. Many other people have since  par-
       ticipated  in  development, testing and support. This manual is part of
       the TigerVNC software suite.

       This    software    was    built    from    source     available     at
       https://github.com/oracle/solaris-userland.    The  original  community
       source was  downloaded  from   https://github.com/TigerVNC/tigervnc/ar-

       Further information about this software can be found on the open source
       community website at http://tigervnc.org/.

TigerVNC                                                        X0VNCSERVER(1)