x0tigervncserver(1)
NAME
x0vncserver - TigerVNC Server for X displays
SYNOPSIS
x0vncserver [options] x0vncserver -version
DESCRIPTION
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.
OPTIONS
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):
-SomeParameter
Enable the parameter, turn the feature on. This form can be
used with parameters that simply enable or disable some feature.
-SomeParameter=0
Disable the parameter, turn the feature off.
-SomeParameter=value
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.
PARAMETERS
display
The X display name. If not specified, it defaults to the value
of the DISPLAY environment variable.
rfbport
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:target: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.
HostsFile
This parameter allows one to specify a file name with IP access
control 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
specified as a number of bits (e.g. /24). Default is to accept
connections from any IP address.
SecurityTypes
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.
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
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, PAMService
PAM service name to use when authentication users using any of
the "Plain" security types. Default is vnc.
X509Cert
Path to a X509 certificate in PEM format to be used for all X509
based security types (X509None, X509Vnc, etc.).
X509Key
Private key counter part to the certificate given in X509Cert.
Must also be in PEM format.
BlacklistThreshold
The number of unauthenticated connection attempts allowed from
any individual host before that host is black-listed. Default
is 5.
BlacklistTimeout
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.
QueryConnect
Prompt the local user to accept or reject incoming connections.
Default is off.
QueryConnectTimeout
Number of seconds to show the Accept Connection dialog before
rejecting the connection. Default is 10.
AlwaysShared
Always treat incoming connections as shared, regardless of the
client-specified setting. Default is off.
NeverShared
Never treat incoming connections as shared, regardless of the
client-specified setting. Default is off.
DisconnectClients
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.
AcceptKeyEvents
Accept key press and release events from clients. Default is
on.
AcceptPointerEvents
Accept pointer events from clients. Default is on.
RemapKeys
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).
Protocol3.3
Always use RFB protocol version 3.3 for backwards compatibility
with badly-behaved clients. Default is off.
Geometry
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).
MaxProcessorUsage
Maximum percentage of CPU time to be consumed when polling the
screen. Default is 35.
PollingCycle
Milliseconds per one polling cycle. Actual interval may be
dynamically adjusted to satisfy MaxProcessorUsage setting.
Default is 30.
DeferUpdate
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
versions of x0vncserver, where the first change to the
framebuffer causes an immediate update to any waiting clients.
AlwaysSetDeferUpdateTimer
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.
CompareFB
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
accelerates reading the screen. Default is on.
OverlayMode
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.
ZlibLevel
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.
ImprovedHextile
Use improved compression algorithm for Hextile encoding which
achieves better compression ratios by the cost of using slightly
more CPU time. Default is on.
IdleTimeout
The number of seconds after which an idle VNC connection will be
dropped (zero means no timeout). Default is 0.
MaxDisconnectionTime
Terminate when no client has been connected for N seconds.
Default is 0.
MaxConnectionTime
Terminate when a client has been connected for N seconds.
Default is 0.
MaxIdleTime
Terminate after N seconds of user inactivity. Default is 0.
ClientWaitTimeMillis
The number of milliseconds to wait for a client which is no
longer responding. Default is 20000.
AcceptCutText
SendCutText
MaxCutText
Currently unused.
SEE ALSO
Xtigervnc(1), tigervncpasswd(1), http://www.tigervnc.org/
AUTHOR
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 participated in development, testing and support. This manual is part of the TigerVNC software suite.
Opportunity
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
Free Books
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Education
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.
