Xvnc(1) TightVNC Xvnc(1)NAMEXvnc - an X server providing VNC connectivity
SYNOPSISXvnc [: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] [-nev-
ershared] [-dontdisconnect] [-viewonly] [-local-
host] [-interface ipaddr] [-inetd] [-compatiblekbd]
[X-options...]
DESCRIPTIONXvnc 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 rea-
sonable defaults for Xvnc session, checks many error con-
ditions etc.
Please read the BUGS section if you plan to use VNC on an
untrusted network.
OPTIONSXvnc 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 out-
put 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 commnunication 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 speci-
fied 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 discon-
nect 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 desk-
top but won't be able to control it.
-localhost
Only allow loopback connections from localhost.
This option is useful in conjunction with SSH tun-
neling.
-interface ipaddr
Listen for client connections only on the network
interface with given ipaddr.
-inetdXvnc 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 implemen-
tation. It's recommended to restrict network access to
Xvnc servers from untrusted network adresses. Probably,
the best way to secure Xvnc server is to allow only loop-
back 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.uk.research.att.com/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 was implemented by Constantin Kaplin-
sky. Many other people participated in development, test-
ing and support.
Man page authors:
Marcus Brinkmann <Marcus.Brinkmann@ruhr-uni-bochum.de>,
Tim Waugh <twaugh@redhat.com>,
Constantin Kaplinsky <const@ce.cctpu.edu.ru>
August 2002 Xvnc(1)
