Ubuntu Manpage: X0tigervnc - TigerVNC Server for X displays

Provided by: tigervnc-scraping-server_1.14.1+dfsg-1_amd64

NAME

       X0tigervnc - TigerVNC Server for X displays

SYNOPSIS

       X0tigervnc [options]
       X0tigervnc -version

DESCRIPTION

       X0tigervnc  is  a  TigerVNC  Server  which  makes  any X display remotely accessible via VNC, TigerVNC or
       compatible viewers.  Unlike Xtigervnc(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 X0tigervnc will fall back to polling
       the screen for changes.

OPTIONS

       X0tigervnc  interprets the command line as a list of parameters with optional values.  Running X0tigervnc
       -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

-desktop desktop-name
Each desktop has a name which may be displayed by the viewer. It defaults to "<user>@<hostname>".

-display display
The X display name. If not specified, it defaults to the value of the DISPLAY environment
variable.

-rfbport port
Specifies the TCP port on which X0tigervnc listens for connections from viewers (the protocol used
in VNC is called RFB - "remote framebuffer"). Specify -1 to disable listening on a TCP port. The
default port is 5900 when started directly, and -1 when activated by a systemd socket.

-UseIPv4
Use IPv4 for incoming and outgoing connections. Default is on.

-UseIPv6
Use IPv6 for incoming and outgoing connections. Default is on.

-rfbunixpath path
Specifies the path of a Unix domain socket on which X0tigervnc listens for connections from
viewers. Default is to not listen to any Unix domain socket.

-rfbunixmode mode
Specifies the mode of the Unix domain socket. The default is 0600.

-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.

-HostsFile filename
This parameter allows 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 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, X509Plain, RA2, RA2ne,
RA2_256 and RA2ne_256. Default is TLSVnc,VncAuth.

-rfbauth passwd-file, -PasswordFile passwd-file
Password file for VNC authentication. There is no default, you should specify the password file
explicitly. Password file should be created with the tigervncpasswd(1) utility. The file is
accessed each time a connection comes in, so it can be changed on the fly.

-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. Specify %u to allow the user of the server process. 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 format.

-GnuTLSPriority priority
GnuTLS priority string that controls the TLS session’s handshake algorithms. See the GnuTLS
manual for possible values. Default is NORMAL.

-RSAKey path
Path to the RSA key for the RSA-AES security types (RA2, RA2ne, RA2_256 and RA2ne_256) in PEM
format.

-RequireUsername
Require username for the RSA-AES security types. Default is off.

-UseBlacklist
Temporarily reject connections from a host if it repeatedly fails to authenticate. Default is on.

-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.

-QueryConnect
Prompts the user of the desktop to explicitly accept or reject incoming connections. Default is
off.

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

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

-interface IP address
Listen on interface. By default X0tigervnc listens on all available interfaces.

-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. 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.

-AcceptKeyEvents
Accept key press and release events from clients. Default is on.

-AcceptPointerEvents
Accept pointer movement and button events from clients. Default is on.

-AcceptSetDesktopSize
Accept requests to resize the size of the desktop. Default is on.

-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 following:

RemapKeys=0x22<>0x40

-RawKeyboard
Send keyboard events straight through and avoid mapping them to the current keyboard layout. This
effectively makes the keyboard behave according to the layout configured on the server instead of
the layout configured on the client. Default is off.

-Protocol3.3
Always use protocol version 3.3 for backwards compatibility with badly-behaved clients. Default is
off.

-Geometry 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 percent
Maximum percentage of CPU time to be consumed when polling the screen. Default is 35.

-PollingCycle milliseconds
Milliseconds per one polling cycle. Actual interval may be dynamically adjusted to satisfy
MaxProcessorUsage setting. Default is 30.

-FrameRate fps
The maximum number of updates per second sent to each client. If the screen updates any faster
then those changes will be aggregated and sent in a single update to the client. Note that this
only controls the maximum rate and a client may get a lower rate when resources are limited.
Default is 60.

-CompareFB mode
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.

-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 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.

AUTHOR