Xvnc(1) TightVNC Xvnc(1)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] [-compati‐
blekbd] [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-spe‐
cific 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 comm‐
nunication 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. Nor‐
mally, Java viewer classes are stored in such directory.
-httpport port
TCP port on which Xvnc should listen for incoming HTTP connec‐
tions (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-spe‐
cific). The "gradient" filter often helps to improve data com‐
pression 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 simulta‐
neous client connections.
-dontdisconnect
Don't disconnect existing clients when a new non-shared connec‐
tion 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> .
SEE ALSOvncserver(1), vncviewer(1), vncpasswd(1), vncconnect(1), sshd(1)AUTHORS
Original VNC was developed in AT&T Laboratories Cambridge. TightVNC
additions were implemented by Constantin Kaplinsky. Many other people
participated in development, testing and support.
Man page authors:
Marcus Brinkmann <Marcus.Brinkmann@ruhr-uni-bochum.de>,
Tim Waugh <twaugh@redhat.com>,
Constantin Kaplinsky <const@tightvnc.com>
August 2006 Xvnc(1)
