Provided by: tigervnc-standalone-server_1.7.0+dfsg-8ubuntu2_amd64 bug


       Xtigervnc - the X VNC server


       Xtigervnc [options] :display#


       Xtigervnc  is  the  X VNC (Virtual Network Computing) server.  It is based on a standard X
       server, but it has a "virtual" screen rather than a physical one.  X applications  display
       themselves on it as if it were a normal X display, but they can only be accessed via a VNC
       viewer - see vncviewer(1).

       So Xtigervnc is really two servers in one. To the applications it is an X server,  and  to
       the  remote  VNC  users  it  is  a VNC server. By convention we have arranged that the VNC
       server display number will be the same as the X server display number, which means you can
       use eg. snoopy:2 to refer to display 2 on machine "snoopy" in both the X world and the VNC

       The best way of starting Xvnc is via the vncserver script.  This sets up  the  environment
       appropriately  and  runs  some  X  applications to get you going.  See the manual page for
       vncserver(1) for more information.


       Xtigervnc takes lots of options - running Xvnc -help gives a  list.   Many  of  these  are
       standard X server options, which are described in the Xserver(1) manual page.  In addition
       to options which can only be set via the command-line, there are also  "parameters"  which
       can be set both via the command-line and through the vncconfig(1) program.

       -geometry widthxheight
              Specify the size of the desktop to be created. Default is 1024x768.

       -depth depth
              Specify  the pixel depth in bits of the desktop to be created. Default is 24, other
              possible values are 8, 15, and 16 -  anything  else  is  likely  to  cause  strange
              behaviour by applications.

       -pixelformat format
              Specify pixel format for server to use (BGRnnn or RGBnnn).  The default for depth 8
              is BGR233 (meaning the most significant two bits represent  blue,  the  next  three
              green,  and the least significant three represent red), the default for depth 16 is
              RGB565 and for depth 24 is RGB888.

       -interface IP address
              Listen on interface. By default Xtigervnc listens on all available interfaces.

       -inetd This significantly changes Xtigervnc's behaviour so that it can  be  launched  from
              inetd.  See the section below on usage with inetd.

       -help  List all the options and parameters


       VNC  parameters can be set both via the command-line and through the vncconfig(1) program,
       and with a VNC-enabled Xorg server via Options entries in the xorg.conf file.

       Parameters can be turned on with -param or off with -param=0.   Parameters  which  take  a
       value  can  be  specified as -param value.  Other valid forms are param=value -param=value
       --param=value.  Parameter names are case-insensitive.

       -desktop desktop-name
              Each desktop has a name which may be displayed by the viewer. It defaults to "x11".

       -rfbport port
              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.

       -rfbwait time, -ClientWaitTimeMillis time

              Time in milliseconds to wait for a viewer which is  blocking  Xtigervnc.   This  is
              necessary  because  Xtigervnc  is  single-threaded  and  sometimes blocks until the
              viewer has finished sending or receiving a message - note that this does  not  mean
              an update will be aborted after this time.  Default is 20000 (20 seconds).

       -httpd directory
              Run  a  mini-HTTP server which serves files from the given directory.  Normally the
              directory will contain the classes for the Java viewer.  In addition, files with  a
              .vnc  extension  will have certain substitutions made so that a single installation
              of the Java VNC viewer can be served by separate instances of Xtigervnc.

       -httpPort port
              Specifies the port on which the mini-HTTP server runs.  Default is  5800  plus  the
              display number.

       -rfbauth passwd-file, -PasswordFile passwd-file
              Specifies  the file containing the password used to authenticate viewers.  The file
              is accessed each time a connection comes in, so it can be changed on  the  fly  via

       -DeferUpdate time
              Xtigervnc  uses  a  "deferred  update" mechanism which enhances performance in many
              cases. After any change to the framebuffer, Xtigervnc  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 versions of Xtigervnc, 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.

              Send  clipboard  changes  to  clients (default is on).  Note that you must also run
              vncconfig(1) to get the clipboard to work.

              Accept clipboard updates from clients (default is on).  Note that you must also run
              vncconfig(1) to get the clipboard to work.

       -MaxCutText bytes
              The  maximum  size  of  a  clipboard  update  that  will be accepted from a client.
              Default is 262144.

              Accept pointer press and release events from clients (default is on).

              Accept key press and release events from clients (default is on).

              Disconnect existing clients if an incoming connection  is  non-shared  (default  is
              on).  If  DisconnectClients  is  false,  then  a  new non-shared connection will be
              refused while there is a client active.  When combined with NeverShared this  means
              only one client is allowed at a time.

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

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

              Always  use  protocol  version  3.3  for backwards compatibility with badly-behaved
              clients (default is off).

              Perform pixel comparison on framebuffer to reduce unnecessary updates  (default  is

              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.

       -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,TLSVnc.

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

       -PlainUsers user-list
              A  comma  separated  list of user names that are allowed to authenticate 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 name, -PAMService name
              PAM service name to use when authentication users using any of the "Plain" security
              types. Default is vnc.

       -X509Cert path
              Path to a X509 certificate in PEM format to be used for  all  X509  based  security
              types (X509None, X509Vnc, etc.).

       -X509Key path
              Private  key counter part to the certificate given in X509Cert. Must also be in PEM

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

       -BlacklistTimeout seconds
              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.

       -IdleTimeout seconds
              The number of seconds after which an idle VNC connection will be  dropped  (default
              is 0, which means that idle connections will never be dropped).

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

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

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

              Prompts   the  user  of  the  desktop  to  explicitly  accept  or  reject  incoming
              connections.  This is most useful when using the  module  or  x0vncserver(1)
              program to access an existing X desktop via VNC.

              The  vncconfig(1)  program must be running on the desktop in order for QueryConnect
              to be supported by the module or  Xvnc(1)  program.   The  x0vncserver(1)
              program does not require vncconfig(1) to be running.

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

              Only allow connections from the same machine. Useful if you use  SSH  and  want  to
              stop non-SSH connections from any other hosts.

       -Log logname:dest:level
              Configures the debug log settings.  dest can currently be stderr, stdout or syslog,
              and level is between 0 and 100,  100  meaning  most  verbose  output.   logname  is
              usually  *  meaning  all, but you can target a specific source file if you know the
              name of its "LogWriter".  Default is *:stderr:30.

       -RemapKeys mapping
              Sets up a keyboard mapping.  mapping  is  a  comma-separated  string  of  character
              mappings,  each  of the form char->char, or char<>char, where char is a hexadecimal
              keysym. For example, to exchange  the  "  and  @  symbols  you  would  specify  the


                 Key  affected  by NumLock often require a fake Shift to be inserted in order for
                 the correct symbol to be generated. Turning on this option  avoids  these  extra
                 fake  Shift  events but may result in a slightly different symbol (e.g. a Return
                 instead of a keypad Enter).

                 Comma separated list of parameters that can be  modified  using  VNC  extension.
                 Parameters  can be modified for example using vncconfig(1) program from inside a
                 running session.

                 Allowing  override  of  parameters  such  as  PAMService  or  PasswordFile   can
                 negatively  impact  security  if  Xtigervnc  runs  under different user than the
                 programs allowed to override the parameters.

                 When  NoClipboard  parameter  is  set,  allowing  override  of  SendCutText  and
                 AcceptCutText has no effect.

                 Default is desktop,AcceptPointerEvents,SendCutText,AcceptCutText.


       By  configuring  the  inetd(1)  service appropriately, Xtigervnc can be launched on demand
       when a connection comes in, rather than having to be started  manually.   When  given  the
       -inetd  option,  instead  of  listening  for  TCP  connections on a given port it uses its
       standard input and standard output.  There are two modes  controlled  by  the  wait/nowait
       entry in the inetd.conf file.

       In  the  nowait  mode,  Xtigervnc  uses  its  standard  input  and  output directly as the
       connection to a viewer.  It never  has  a  listening  socket,  so  cannot  accept  further
       connections  from  viewers  (it can however connect out to listening viewers by use of the
       tigervncconfig program).  Further viewer connections to the same TCP port result in  inetd
       spawning  off  a  new  Xtigervnc to deal with each connection.  When the connection to the
       viewer dies, the Xtigervnc and any associated X  clients  die.   This  behaviour  is  most
       useful  when  combined  with  the  XDMCP  options -query and -once.  An typical example in
       inetd.conf might be (all on one line):

       5950   stream    tcp  nowait  nobody   /usr/local/bin/Xtigervnc  Xtigervnc  -inetd  -query
       localhost -once securitytypes=none

       In  this  example  a  viewer  connection  to  :50  will result in a new Xtigervnc for that
       connection which should display the standard XDM login screen on  that  machine.   Because
       the  user  needs  to  login  via XDM, it is usually OK to accept connections without a VNC
       password in this case.

       In the wait mode, when the first connection comes in, inetd gives the listening socket  to
       Xtigervnc.   This  means  that for a given TCP port, there is only ever one Xtigervnc at a
       time.  Further viewer connections to the same port are accepted by the same  Xtigervnc  in
       the  normal way.  Even when the original connection is broken, the Xtigervnc will continue
       to run.  If this is used with the XDMCP  options  -query  and  -once,  the  Xtigervnc  and
       associated  X  clients will die when the user logs out of the X session in the normal way.
       It is important to use a VNC password in this case.  A typical entry in  inetd.conf  might

       5951    stream    tcp  wait    james      /usr/local/bin/Xtigervnc Xtigervnc -inetd -query
       localhost -once passwordFile=/home/james/.vnc/passwd

       In fact typically, you would have one entry for each user who uses VNC regularly, each  of
       whom  has their own dedicated TCP port which they use.  In this example, when user "james"
       connects to :51, he enters his VNC password, then gets the XDM login screen where he  logs
       in  in  the  normal  way.   However,  unlike  the previous example, if he disconnects, the
       session remains persistent, and when he reconnects he  will  get  the  same  session  back
       again.  When he logs out of the X session, the Xtigervnc will die, but of course a new one
       will be created automatically the next time he connects.


       tigervncconfig(1), tigervncpasswd(1), tigervncserver(1),  xtigervncviewer(1),  Xserver(1),


       Tristan Richardson, RealVNC Ltd. 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 participated in development, testing and support. This manual is
       part of the TigerVNC software suite.