Ubuntu Manpage: Xvnc - an X server providing VNC connectivity

Provided by: tightvncserver_1.3.10-5_amd64

NAME

       Xvnc - an X server providing VNC connectivity

SYNOPSIS

       Xvnc   [:display]  [-geometry  widthxheight]  [-depth  depth] [-pixelformat rgbNNN|bgrNNN]
              [-udpinputport port] [-rfbport port] [-rfbwait time] [-nocursor] [-rfbauth  passwd-
              file]  [-httpd  dir]  [-httpport  port]  [-deferupdate  time]  [-economictranslate]
              [-lazytight]  [-desktop  name]  [-alwaysshared]  [-nevershared]   [-dontdisconnect]
              [-viewonly]   [-localhost]   [-interface   ipaddr]  [-inetd]  [-compatiblekbd]  [X-
              options...]

DESCRIPTION

       Xvnc is a VNC (Virtual Network Computing) server. It acts like an X server with a  virtual
       display.  The  display  can be seen by a VNC viewer application, which may be running on a
       different machine: see vncviewer(1). Xvnc is built inside the source code tree of XFree86,
       and shares many options with it.

       Normally,  you  don't  need  to  start  Xvnc manually; use the vncserver(1) wrapper script
       instead. This script  sets  reasonable  defaults  for  Xvnc  session,  checks  many  error
       conditions etc.

       Please read the BUGS section if you plan to use VNC on an untrusted network.

OPTIONS

Xvnc supports many standard X server options and a number of VNC-specific options. To see
what standard X server options are supported, please look at the Xvnc -help output and
read the Xserver(1) manual page for details on those options.

The VNC-specific options are as follows:

-geometry widthxheight
Set desktop width and height.

-depth depth
Set the colour depth of the visual to provide, in bits per pixel. Must be a value
between 8 and 32.

-pixelformat rgbNNN|bgrNNN
Set colour format for pixels representation. The viewer can do the conversion to
any other pixel format, but it is faster if the depth and pixel format of the
server is the same as the equivalent values on the viewer display.

-udpinputport port
UDP port for keyboard/pointer data.

-rfbport port
TCP port for RFB protocol. The RFB protocol is used for communication between VNC
server and clients.

-rfbwait time
Maximum time, in milliseconds, to wait for an RFB client (VNC viewer).

-nocursor
Don't put up a pointer cursor on the desktop.

-rfbauth passwd-file
Use authentication on RFB protocol from the specified file. The passwd-file can be
created using the vncpasswd(1) utility.

-httpd dir
Serve files via HTTP protocol from the specified directory. Normally, Java viewer
classes are stored in such directory.

-httpport port
TCP port on which Xvnc should listen for incoming HTTP connections (to allow access
to the desktop from any Java-capable browser).

-deferupdate time
Time in milliseconds, to defer screen updates (default 40). Deferring updates helps
to coalesce many small desktop changes into a few larger updates thus saving
network bandwidth.

-economictranslate
Use less memory-hungry pixel format translation.

-lazytight
Disable the "gradient" filter in Tight encoding (TightVNC-specific). The
"gradient" filter often helps to improve data compression ratios, but may slow down
the server performance. Please note that this filter is never used when a client
enables JPEG compression in the Tight encoding.

-desktop name
Set VNC desktop name ("x11" by default).

-alwaysshared
Always treat new clients as shared, never disconnect existing client on a new
client connection.

-nevershared
Never treat new clients as shared, do not allow several simultaneous client
connections.

-dontdisconnect
Don't disconnect existing clients when a new non-shared connection comes in, refuse
new connection instead.

-viewonly
Don't accept keboard and pointer events from clients. All clients will be able to
see the desktop but won't be able to control it.

-localhost
Only allow loopback connections from localhost. This option is useful in
conjunction with SSH tunneling.

-interface ipaddr
Listen for client connections only on the network interface with given ipaddr.

-inetd Xvnc is launched by inetd. This option causes Xvnc to redirect network input/output
to stdin/stdout.

-compatiblekbd
Set META and ALT keys to the same X modifier flag, as in the original version of
Xvnc by AT&T labs (TightVNC-specific).

BUGS

       There are many security problems in  current  Xvnc  implementation.  It's  recommended  to
       restrict  network  access  to Xvnc servers from untrusted network addresses. Probably, the
       best way to secure Xvnc server is to allow  only  loopback  connections  from  the  server
       machine  (the  -localhost  option)  and to use SSH tunneling for remote access to the Xvnc
       server.         For         details         on         SSH         tunneling,          see
       <URL:http://www.cl.cam.ac.uk/Research/DTG/attarchive/vnc/sshvnc.html> .

AUTHORS