.\" This file was automatically generated from x11vnc -help output. .TH X11VNC "1" "April 2006" "x11vnc " "User Commands" .SH NAME x11vnc - allow VNC connections to real X11 displays version: 0.8.1, lastmod: 2006-04-25 .SH SYNOPSIS .B x11vnc [OPTION]... .SH DESCRIPTION .PP Typical usage is: .IP Run this command in a shell on the remote machine "far-host" with X session you wish to view: .IP x11vnc -display :0 .IP Then run this in another window on the machine you are sitting at: .IP vncviewer far-host:0 .PP Once x11vnc establishes connections with the X11 server and starts listening as a VNC server it will print out a string: PORT=XXXX where XXXX is typically 5900 (the default VNC server port). One would next run something like this on the local machine: "vncviewer hostname:N" where "hostname" is the name of the machine running x11vnc and N is XXXX - 5900, i.e. usually "vncviewer hostname:0". .PP By default x11vnc will not allow the screen to be shared and it will exit as soon as the client disconnects. See \fB-shared\fR and \fB-forever\fR below to override these protections. See the FAQ for details how to tunnel the VNC connection through an encrypted channel such as .IR ssh (1). In brief: .PP % ssh -L 5900:localhost:5900 far-host 'x11vnc -localhost -display :0' .PP % vncviewer -encodings 'copyrect tight zrle hextile' localhost:0 .PP Also, use of a VNC password (-rfbauth or \fB-passwdfile)\fR is strongly recommend. .PP For additional info see: http://www.karlrunge.com/x11vnc/ and http://www.karlrunge.com/x11vnc/#faq .PP Rudimentary config file support: if the file $HOME/.x11vncrc exists then each line in it is treated as a single command line option. Disable with \fB-norc.\fR For each option name, the leading character "-" is not required. E.g. a line that is either "forever" or "\fB-forever\fR" may be used and are equivalent. Likewise "wait 100" or "\fB-wait\fR \fI100\fR" are acceptable and equivalent lines. The "#" character comments out to the end of the line in the usual way (backslash it for a literal). Leading and trailing whitespace is trimmed off. Lines may be continued with a "\\" as the last character of a line (it becomes a space character). .PP .SH OPTIONS .PP \fB-display\fR \fIdisp\fR .IP X11 server display to connect to, usually :0. The X server process must be running on same machine and support MIT-SHM. Equivalent to setting the DISPLAY environment variable to \fIdisp\fR. .PP \fB-auth\fR \fIfile\fR .IP Set the X authority file to be \fIfile\fR, equivalent to setting the XAUTHORITY environment variable to \fIfile\fR before startup. Same as \fB-xauth\fR file. See .IR Xsecurity (7) , .IR xauth (1) man pages for more info. .PP \fB-id\fR \fIwindowid\fR .IP Show the window corresponding to \fIwindowid\fR not the entire display. New windows like popup menus, transient toplevels, etc, may not be seen or may be clipped. Disabling SaveUnders or BackingStore in the X server may help show them. x11vnc may crash if the window is initially partially obscured, changes size, is iconified, etc. Some steps are taken to avoid this and the \fB-xrandr\fR mechanism is used to track resizes. Use .IR xwininfo (1) to get the window id, or use "\fB-id\fR \fIpick\fR" to have x11vnc run .IR xwininfo (1) for you and extract the id. The \fB-id\fR option is useful for exporting very simple applications (e.g. the current view on a webcam). .PP \fB-sid\fR \fIwindowid\fR .IP As \fB-id,\fR but instead of using the window directly it shifts a root view to it: this shows SaveUnders menus, etc, although they will be clipped if they extend beyond the window. .PP \fB-clip\fR \fIWxH+X+Y\fR .IP Only show the sub-region of the full display that corresponds to the rectangle with size WxH and offset +X+Y. The VNC display has size WxH (i.e. smaller than the full display). This also works for \fB-id/-sid\fR mode where the offset is relative to the upper left corner of the selected window. .PP \fB-flashcmap\fR .IP In 8bpp indexed color, let the installed colormap flash as the pointer moves from window to window (slow). Also try the \fB-8to24\fR option to avoid flash altogether. .PP \fB-shiftcmap\fR \fIn\fR .IP Rare problem, but some 8bpp displays use less than 256 colorcells (e.g. 16-color grayscale, perhaps the other bits are used for double buffering) *and* also need to shift the pixels values away from 0, .., ncells. \fIn\fR indicates the shift to be applied to the pixel values. To see the pixel values set DEBUG_CMAP=1 to print out a colormap histogram. Example: \fB-shiftcmap\fR 240 .PP \fB-notruecolor\fR .IP For 8bpp displays, force indexed color (i.e. a colormap) even if it looks like 8bpp TrueColor (rare problem). .PP \fB-visual\fR \fIn\fR .IP Experimental option: probably does not do what you think. It simply *forces* the visual used for the framebuffer; this may be a bad thing... (e.g. messes up colors or cause a crash). It is useful for testing and for some workarounds. n may be a decimal number, or 0x hex. Run .IR xdpyinfo (1) for the values. One may also use "TrueColor", etc. see for a list. If the string ends in ":m" then for better or for worse the visual depth is forced to be m. .PP \fB-overlay\fR .IP Handle multiple depth visuals on one screen, e.g. 8+24 and 24+8 overlay visuals (the 32 bits per pixel are packed with 8 for PseudoColor and 24 for TrueColor). .IP Currently \fB-overlay\fR only works on Solaris via .IR XReadScreen (3X11) and IRIX using .IR XReadDisplay (3). On Solaris there is a problem with image "bleeding" around transient popup menus (but not for the menu itself): a workaround is to disable SaveUnders by passing the "\fB-su\fR" argument to Xsun (in /etc/dt/config/Xservers). .IP Use \fB-overlay\fR as a workaround for situations like these: Some legacy applications require the default visual to be 8bpp (8+24), or they will use 8bpp PseudoColor even when the default visual is depth 24 TrueColor (24+8). In these cases colors in some windows will be incorrect in x11vnc unless \fB-overlay\fR is used. Another use of \fB-overlay\fR is to enable showing the exact mouse cursor shape (details below). .IP Under \fB-overlay,\fR performance will be somewhat slower due to the extra image transformations required. For optimal performance do not use \fB-overlay,\fR but rather configure the X server so that the default visual is depth 24 TrueColor and try to have all apps use that visual (e.g. some apps have \fB-use24\fR or \fB-visual\fR options). .PP \fB-overlay_nocursor\fR .IP Sets \fB-overlay,\fR but does not try to draw the exact mouse cursor shape using the overlay mechanism. .PP \fB-8to24\fR \fI[opts]\fR .IP Try this option if \fB-overlay\fR is not supported on your OS, and you have a legacy 8bpp app that you want to view on a multi-depth display with default depth 24 (and is 32 bpp) OR have a default depth 8 display with depth 24 overlay windows for some apps. This option may not work on all X servers and hardware (tested on XFree86/Xorg mga driver and Xsun). The "opts" string is not required and is described below. .IP This mode enables a hack where x11vnc monitors windows within 3 levels from the root window. If it finds any that are 8bpp it extracts the indexed color pixel values using XGetImage() and then applies a transformation using the colormap(s) to create TrueColor RGB values that it in turn inserts into bits 1-24 of the framebuffer. This creates a depth 24 "view" of the display that is then exported via VNC. .IP Conversely, for default depth 8 displays, the depth 24 regions are read by XGetImage() and everything is transformed and inserted into a depth 24 TrueColor framebuffer. .IP Note that even if there are *no* depth 24 visuals or windows (i.e. pure 8bpp), this mode is potentially an improvement over \fB-flashcmap\fR because it avoids the flashing and shows each window in the correct color. .IP This method appear to work, but may still have bugs and it does hog resources. If there are multiple 8bpp windows using different colormaps, one may have to iconify all but one for the colors to be correct. .IP There may be painting errors for clipping and switching between windows of depths 8 and 24. Heuristics are applied to try to minimize the painting errors. One can also press 3 Alt_L's in a row to refresh the screen if the error does not repair itself. Also the option \fB-fixscreen\fR 8=3.0 or \fB-fixscreen\fR V=3.0 may be used to periodically refresh the screen at the cost of bandwidth (every 3 sec for this example). .IP The [opts] string can contain the following settings. Multiple settings are separated by commas. .IP For for some X servers with default depth 24 a speedup may be achieved via the option "nogetimage". This enables a scheme were XGetImage() is not used to retrieve the 8bpp data. Instead, it assumes that the 8bpp data is in bits 25-32 of the 32bit X pixels. There is no reason the X server should put the data there for our poll requests, but some do and so the extra steps to retrieve it can be skipped. Tested with mga driver with XFree86/Xorg. For the default depth 8 case this option is ignored. .IP To adjust how often XGetImage() is used to poll the non-default visual regions for changes, use the option "poll=t" where "t" is a floating point time. (default: 0.05) .IP Setting the option "level2" will limit the search for non-default visual windows to two levels from the root window. Do this on slow machines where you know the window manager only imposes one extra window between the app window and the root window. .IP Also for very slow machines use "cachewin=t" where t is a floating point amount of time to cache XGetWindowAttributes results. E.g. cachewin=5.0. This may lead to the windows being unnoticed for this amount of time when deiconifying, painting errors, etc. .IP While testing on a very old SS20 these options gave tolerable response: \fB-8to24\fR poll=0.2,cachewin=5.0. For this machine \fB-overlay\fR is supported and gives better response. .IP Debugging for this mode can be enabled by setting "dbg=1", "dbg=2", or "dbg=3". .PP \fB-scale\fR \fIfraction\fR .IP Scale the framebuffer by factor \fIfraction\fR. Values less than 1 shrink the fb, larger ones expand it. Note: image may not be sharp and response may be slower. If \fIfraction\fR contains a decimal point "." it is taken as a floating point number, alternatively the notation "m/n" may be used to denote fractions exactly, e.g. \fB-scale\fR 2/3 .IP Scaling Options: can be added after \fIfraction\fR via ":", to supply multiple ":" options use commas. If you just want a quick, rough scaling without blending, append ":nb" to \fIfraction\fR (e.g. \fB-scale\fR 1/3:nb). No blending is the default for 8bpp indexed color, to force blending for this case use ":fb". .IP To disable \fB-scrollcopyrect\fR and \fB-wirecopyrect\fR under \fB-scale\fR use ":nocr". If you need to to enable them use ":cr" or specify them explicitly on the command line. If a slow link is detected, ":nocr" may be applied automatically. Default: :cr .IP More esoteric options: for compatibility with vncviewers the scaled width is adjusted to be a multiple of 4: to disable this use ":n4". ":in" use interpolation scheme even when shrinking, ":pad" pad scaled width and height to be multiples of scaling denominator (e.g. 3 for 2/3). .PP \fB-scale_cursor\fR \fIfrac\fR .IP By default if \fB-scale\fR is supplied the cursor shape is scaled by the same factor. Depending on your usage, you may want to scale the cursor independently of the screen or not at all. If you specify \fB-scale_cursor\fR the cursor will be scaled by that factor. When using \fB-scale\fR mode to keep the cursor at its "natural" size use "\fB-scale_cursor\fR \fI1\fR". Most of the ":" scaling options apply here as well. .PP \fB-viewonly\fR .IP All VNC clients can only watch (default off). .PP \fB-shared\fR .IP VNC display is shared, i.e. more than one viewer can connect at the same time (default off). .PP \fB-once\fR .IP Exit after the first successfully connected viewer disconnects, opposite of \fB-forever.\fR This is the Default. .PP \fB-forever\fR .IP Keep listening for more connections rather than exiting as soon as the first client(s) disconnect. Same as \fB-many\fR .PP \fB-loop\fR .IP Create an outer loop restarting the x11vnc process whenever it terminates. \fB-bg\fR and \fB-inetd\fR are ignored in this mode. Useful for continuing even if the X server terminates and restarts (you will need permission to reconnect of course). Use, e.g., \fB-loop100\fR to sleep 100 millisecs between restarts, etc. Default is 2000ms (i.e. 2 secs) Use, e.g. \fB-loop300,5\fR to sleep 300 ms and only loop 5 times. .PP \fB-timeout\fR \fIn\fR .IP Exit unless a client connects within the first n seconds after startup. .PP \fB-inetd\fR .IP Launched by .IR inetd (1): stdio instead of listening socket. Note: if you are not redirecting stderr to a log file (via shell 2> or \fB-o\fR option) you MUST also specify the \fB-q\fR option, otherwise the stderr goes to the viewer which will cause it to abort. Specifying both \fB-inetd\fR and \fB-q\fR and no \fB-o\fR will automatically close the stderr. .PP \fB-nofilexfer\fR .IP Disable the TightVNC file transfer extension. (same as \fB-disablefiletransfer).\fR Note that when the \fB-viewonly\fR option is supplied all file transfers are disabled. Also clients that log in viewonly cannot transfer files. However, if the remote control mechanism is used to change the global or per-client viewonly state the filetransfer permissions will NOT change. .PP \fB-http\fR .IP Instead of using \fB-httpdir\fR (see below) to specify where the Java vncviewer applet is, have x11vnc try to *guess* where the directory is by looking relative to the program location and in standard locations (/usr/local/share/x11vnc/classes, etc). .PP \fB-connect\fR \fIstring\fR .IP For use with "vncviewer -listen" reverse connections. If \fIstring\fR has the form "host" or "host:port" the connection is made once at startup. Use commas for a list of host's and host:port's. .IP Note that unlike most vnc servers, x11vnc will require a password for reverse as well as for forward connections. (provided password auth has been enabled, \fB-rfbauth,\fR etc) If you do not want to require a password for reverse connections set X11VNC_REVERSE_CONNECTION_NO_AUTH=1 in your environment before starting x11vnc. .IP If \fIstring\fR contains "/" it is instead interpreted as a file to periodically check for new hosts. The first line is read and then the file is truncated. Be careful for this usage mode if x11vnc is running as root (e.g. via .IR gdm (1) , etc). .PP \fB-vncconnect,\fR \fB-novncconnect\fR .IP Monitor the VNC_CONNECT X property set by the standard VNC program .IR vncconnect (1). When the property is set to "host" or "host:port" establish a reverse connection. Using .IR xprop (1) instead of vncconnect may work (see the FAQ). The \fB-remote\fR control mechanism uses X11VNC_REMOTE channel, and this option disables/enables it as well. Default: \fB-vncconnect\fR .PP \fB-allow\fR \fIhost1[,host2..]\fR .IP Only allow client connections from hosts matching the comma separated list of hostnames or IP addresses. Can also be a numerical IP prefix, e.g. "192.168.100." to match a simple subnet, for more control build libvncserver with libwrap support (See the FAQ). If the list contains a "/" it instead is a interpreted as a file containing addresses or prefixes that is re-read each time a new client connects. Lines can be commented out with the "#" character in the usual way. .PP \fB-localhost\fR .IP Same as "\fB-allow\fR \fI127.0.0.1\fR". .IP Note: if you want to restrict which network interface x11vnc listens on, see the \fB-listen\fR option below. E.g. "\fB-listen\fR \fIlocalhost\fR" or "\fB-listen\fR \fI192.168.3.21\fR". As a special case, the option "\fB-localhost\fR" implies "\fB-listen\fR \fIlocalhost\fR". .IP For non-localhost \fB-listen\fR usage, if you use the remote control mechanism (-R) to change the \fB-listen\fR interface you may need to manually adjust the \fB-allow\fR list (and vice versa) to avoid situations where no connections (or too many) are allowed. .PP \fB-nolookup\fR .IP Do not use gethostbyname() or gethostbyaddr() to look up host names or IP numbers. Use this if name resolution is incorrectly set up and leads to long pauses as name lookups time out, etc. .PP \fB-input\fR \fIstring\fR .IP Fine tuning of allowed user input. If \fIstring\fR does not contain a comma "," the tuning applies only to normal clients. Otherwise the part before "," is for normal clients and the part after for view-only clients. "K" is for Keystroke input, "M" for Mouse-motion input, "B" for Button-click input, and "C" is for Clipboard input. Their presence in the string enables that type of input. E.g. "\fB-input\fR \fIM\fR" means normal users can only move the mouse and "\fB-input\fR \fIKMBC,M\fR" lets normal users do anything and enables view-only users to move the mouse. This option is ignored when a global \fB-viewonly\fR is in effect (all input is discarded in that case). .PP \fB-viewpasswd\fR \fIstring\fR .IP Supply a 2nd password for view-only logins. The \fB-passwd\fR (full-access) password must also be supplied. .PP \fB-passwdfile\fR \fIfilename\fR .IP Specify the libvncserver password via the first line of the file \fIfilename\fR (instead of via \fB-passwd\fR on the command line where others might see it via .IR ps (1) ). See below for how to supply multiple passwords. .IP If the filename is prefixed with "rm:" it will be removed after being read. Perhaps this is useful in limiting the readability of the file. In general, the password file should not be readable by untrusted users (BTW: neither should the VNC \fB-rfbauth\fR file: it is NOT encrypted). .IP If the filename is prefixed with "read:" it will periodically be checked for changes and reread. .IP Note that only the first 8 characters of a password are used. .IP If multiple non-blank lines exist in the file they are all taken as valid passwords. Blank lines are ignored. Password lines may be "commented out" (ignored) if they begin with the charactor "#" or the line contains the string "__SKIP__". Lines may be annotated by use of the "__COMM__" string: from it to the end of the line is ignored. An empty password may be specified via the "__EMPTY__" string on a line by itself (note your viewer might not accept empty passwords). .IP If the string "__BEGIN_VIEWONLY__" appears on a line by itself, the remaining passwords are used for viewonly access. For compatibility, as a special case if the file contains only two password lines the 2nd one is automatically taken as the viewonly password. Otherwise the "__BEGIN_VIEWONLY__" token must be used to have viewonly passwords. (tip: make the 3rd and last line be "__BEGIN_VIEWONLY__" to have 2 full-access passwords) .PP \fB-unixpw\fR \fI[list]\fR .IP Use Unix username and password authentication. x11vnc uses the .IR su (1) program to verify the user's password. [list] is an optional comma separated list of allowed Unix usernames. See below for per-user options that can be applied. .IP A familiar "login:" and "Password:" dialog is presented to the user on a black screen inside the vncviewer. The connection is dropped if the user fails to supply the correct password in 3 tries or does not send one before a 25 second timeout. Existing clients are view-only during this period. .IP Since the detailed behavior of .IR su (1) can vary from OS to OS and for local configurations, test the mode carefully on your systems before using it in production. Test different combinations of valid/invalid usernames and valid/invalid passwords to see if it behaves as expected. x11vnc will attempt to be conservative and reject a login if anything abnormal occurs. .IP On FreeBSD and the other BSD's by default it is impossible for the user running x11vnc to validate his *own* password via .IR su (1) (evidently commenting out the pam_self.so entry in /etc/pam.d/su eliminates this problem). So the x11vnc login will always *fail* for this case (even when the correct password is supplied). .IP A possible workaround for this would be to start x11vnc as root with the "\fB-users\fR \fI+nobody\fR" option to immediately switch to user nobody. Another source of problems are PAM modules that prompt for extra info, e.g. password aging modules. These logins will fail as well even when the correct password is supplied. .IP **IMPORTANT**: to prevent the Unix password being sent in *clear text* over the network, one of two schemes will be enforced: 1) the \fB-ssl\fR builtin SSL mode, or 2) require both \fB-localhost\fR and \fB-stunnel\fR be enabled. .IP Method 1) ensures the traffic is encrypted between viewer and server. A PEM file will be required, see the discussion under \fB-ssl\fR below (under some circumstances a temporary one can be automatically generated). .IP Method 2) requires the viewer connection to appear to come from the same machine x11vnc is running on (e.g. from a ssh \fB-L\fR port redirection). And that the \fB-stunnel\fR SSL mode be used for encryption over the network.(see the description of \fB-stunnel\fR below). .IP Note: as a convenience, if you .IR ssh (1) in and start x11vnc it will check if the environment variable SSH_CONNECTION is set and appears reasonable. If it does, then the \fB-ssl\fR or \fB-stunnel\fR requirement will be dropped since it is assumed you are using ssh for the encrypted tunnelling. \fB-localhost\fR is still enforced. Use \fB-ssl\fR or \fB-stunnel\fR to force SSL usage even if SSH_CONNECTION is set. .IP To override the above restrictions you can set environment variables before starting x11vnc: .IP Set UNIXPW_DISABLE_SSL=1 to disable requiring either \fB-ssl\fR or \fB-stunnel.\fR Evidently you will be using a different method to encrypt the data between the vncviewer and x11vnc: perhaps .IR ssh (1) or an IPSEC VPN. .IP Note that use of \fB-localhost\fR with .IR ssh (1) is roughly the same as requiring a Unix user login (since a Unix password or the user's public key authentication is used by sshd on the machine where x11vnc runs and only local connections from that machine are accepted) .IP Set UNIXPW_DISABLE_LOCALHOST=1 to disable the \fB-localhost\fR requirement in Method 2). One should never do this (i.e. allow the Unix passwords to be sniffed on the network). .IP Regarding reverse connections (e.g. \fB-R\fR connect:host and \fB-connect\fR host), when the \fB-localhost\fR constraint is in effect then reverse connections can only be used to connect to the same machine x11vnc is running on (default port 5500). Please use a ssh or stunnel port redirection to the viewer machine to tunnel the reverse connection over an encrypted channel. Note that in \fB-ssl\fR mode reverse connection are disabled (see below). .IP In \fB-inetd\fR mode the Method 1) will be enforced (not Method 2). With \fB-ssl\fR in effect reverse connections are disabled. If you override this via env. var, be sure to also use encryption from the viewer to inetd. Tip: you can also have your own stunnel spawn x11vnc in \fB-inetd\fR mode (thereby bypassing inetd). See the FAQ for details. .IP The user names in the comma separated [list] can have per-user options after a ":", e.g. "fred:opts" where "opts" is a "+" separated list of "viewonly", "fullaccess", "input=XXXX", or "deny", e.g. "karl,fred:viewonly,boss:input=M". For "input=" it is the K,M,B,C described under \fB-input.\fR .IP If a user in the list is "*" that means those options apply to all users. It also means all users are allowed to log in after supplying a valid password. Use "deny" to explicitly deny some users if you use "*" to set a global option. .IP There are also some utilities for testing password if [list] starts with the "%" character. See the quick_pw() function in the source for details. .PP \fB-unixpw_nis\fR \fI[list]\fR .IP As \fB-unixpw\fR above, however do not use .IR su (1) but rather use the traditional .IR getpwnam (3) + .IR crypt (3) method to verify passwords instead. This requires that the encrypted passwords be readable. Passwords stored in /etc/shadow will be inaccessible unless x11vnc is run as root. .IP This is called "NIS" mode simply because in most NIS setups the user encrypted passwords are accessible (e.g. "ypcat passwd"). NIS is not required for this mode to work (only that .IR getpwnam (3) return the encrypted password is required), but it is unlikely it will work for any other modern environment. All of the \fB-unixpw\fR options and contraints apply. .PP \fB-ssl\fR \fI[pem]\fR .IP Use the openssl library (www.openssl.org) to provide a built-in encrypted SSL tunnel between VNC viewers and x11vnc. This requires libssl support to be compiled into x11vnc at build time. If x11vnc is not built with libssl support it will exit immediately when \fB-ssl\fR is prescribed. .IP [pem] is optional, use "\fB-ssl\fR \fI/path/to/mycert.pem\fR" to specify a PEM certificate file to use to identify and provide a key for this server. See .IR openssl (1) for more info about PEMs and the \fB-sslGenCert\fR option below. .IP The connecting VNC viewer SSL tunnel can optionally authenticate this server if they have the public key part of the certificate (or a common certificate authority, CA, is a more sophisicated way to verify this server's cert, see \fB-sslGenCA\fR below). This is used to prevent man-in-the-middle attacks. Otherwise, if the VNC viewer accepts this server's key without verification, at least the traffic is protected from passive sniffing on the network (but NOT from man-in-the-middle attacks). .IP If [pem] is not supplied and the .IR openssl (1) utility command exists in PATH, then a temporary, self-signed certificate will be generated for this session (this may take 5-30 seconds on slow machines). If .IR openssl (1) cannot be used to generate a temporary certificate x11vnc exits immediately. .IP If successful in using .IR openssl (1) to generate a temporary certificate, the public part of it will be displayed to stderr (e.g. one could copy it to the client-side to provide authentication of the server to VNC viewers.) See following paragraphs for how to save keys to reuse when x11vnc is restarted. .IP Set the env. var. X11VNC_SHOW_TMP_PEM=1 to have x11vnc print out the entire certificate, including the PRIVATE KEY part, to stderr. One could reuse this cert if saved in a [pem] file. Similarly, set X11VNC_KEEP_TMP_PEM=1 to not delete the temporary PEM file: the file name will be printed to stderr (so one could move it to a safe place for reuse). You will be prompted for a passphrase for the private key. .IP If [pem] is "SAVE" then the certificate will be saved to the file ~/.vnc/certs/server.pem, or if that file exists it will be used directly. Similarly, if [pem] is "SAVE_PROMPT" the server.pem certificate will be made based on your answers to its prompts for info such as OrganizationalName, CommonName, etc. .IP Use "SAVE-" and "SAVE_PROMPT-" to refer to the file ~/.vnc/certs/server-.pem instead. E.g. "SAVE-charlie" will store to the file ~/.vnc/certs/server-charlie.pem .IP See \fB-ssldir\fR below to use a directory besides the default ~/.vnc/certs .IP Example: x11vnc \fB-ssl\fR SAVE \fB-display\fR :0 ... .IP Reverse connections are disabled in \fB-ssl\fR mode because there is no way to ensure that data channel will be encrypted. Set X11VNC_SSL_ALLOW_REVERSE=1 to override this. .IP Your VNC viewer will also need to be able to connect via SSL. See the discussion below under \fB-stunnel\fR and the FAQ (ssl_vncviewer script) for how this might be achieved. E.g. on Unix it is easy to write a shell script that starts up stunnel and then vncviewer. Also in the x11vnc source a SSL enabled Java VNC Viewer applet is provided in the classes/ssl directory. .PP \fB-ssldir\fR \fI[dir]\fR .IP Use [dir] as an alternate ssl certificate and key management toplevel directory. The default is ~/.vnc/certs .IP This directory is used to store server and other certificates and keys and also other materials. E.g. in the simplest case, "\fB-ssl\fR \fISAVE\fR" will store the x11vnc server cert in [dir]/server.pem .IP Use of alternate directories via \fB-ssldir\fR allows you to manage multiple VNC Certificate Authority (CA) keys. Another use is if ~/.vnc/cert is on an NFS share you might want your certificates and keys to be on a local filesystem to prevent network snooping (for example \fB-ssldir\fR /var/lib/x11vnc-certs). .IP \fB-ssldir\fR affects nearly all of the other \fB-ssl*\fR options, e.g. \fB-ssl\fR SAVE, \fB-sslGenCert,\fR etc.. .PP \fB-sslverify\fR \fI[path]\fR .IP For either of the \fB-ssl\fR or \fB-stunnel\fR modes, use [path] to provide certificates to authenticate incoming VNC *Client* connections (normally only the server is authenticated in SSL.) This can be used as a method to replace standard password authentication of clients. .IP If [path] is a directory it contains the client (or CA) certificates in separate files. If [path] is a file, it contains multiple certificates. See special tokens below. These correspond to the "CApath = dir" and "CAfile = file" stunnel options. See the .IR stunnel (8) manpage for details. .IP Examples: x11vnc \fB-ssl\fR \fB-sslverify\fR ~/my.pem x11vnc \fB-ssl\fR \fB-sslverify\fR ~/my_pem_dir/ .IP Note that if [path] is a directory, it must contain the certs in separate files named like .0, where the value of is found by running the command "openssl x509 \fB-hash\fR \fB-noout\fR \fB-in\fR file.crt". Evidently one uses .1 if there is a collision... .IP The the key-management utility "\fB-sslCertInfo\fR \fIHASHON\fR" and "\fB-sslCertInfo\fR \fIHASHOFF\fR" will create/delete these hashes for you automatically (via symlink) in the HASH subdirs it manages. Then you can point \fB-sslverify\fR to the HASH subdir. .IP Special tokens: in \fB-ssl\fR mode, if [path] is not a file or a directory, it is taken as a comma separated list of tokens that are interpreted as follows: .IP If a token is "CA" that means load the CA/cacert.pem file from the ssl directory. If a token is "clients" then all the files clients/*.crt in the ssl directory are loaded. Otherwise the file clients/token.crt is attempted to be loaded. As a kludge, use a token like ../server-foo to load a server cert if you find that necessary. .IP Use \fB-ssldir\fR to use a directory different from the ~/.vnc/certs default. .IP Note that if the "CA" cert is loaded you do not need to load any of the certs that have been signed by it. You will need to load any additional self-signed certs however. .IP Examples: x11vnc \fB-ssl\fR \fB-sslverify\fR CA x11vnc \fB-ssl\fR \fB-sslverify\fR self:fred,self:jim x11vnc \fB-ssl\fR \fB-sslverify\fR CA,clients .IP Usually "\fB-sslverify\fR \fICA\fR" is the most effective. See the \fB-sslGenCA\fR and \fB-sslGenCert\fR options below for how to set up and manage the CA framework. .IP NOTE: the following utilities, \fB-sslGenCA,\fR \fB-sslGenCert,\fR \fB-sslEncKey,\fR and \fB-sslCertInfo\fR are provided for completeness, but for casual usage they are overkill. .IP They provide VNC Certificate Authority (CA) key creation and server / client key generation and signing. So they provide a basic Public Key management framework for VNC-ing with x11vnc. (note that they require .IR openssl (1) be installed on the system) .IP However, the simplest usage mode (where x11vnc automatically generates its own, self-signed, temporary key and the VNC viewers always accept it, e.g. accepting via a dialog box) is probably safe enough for most scenarios. CA management is not needed. .IP To protect against Man-In-The-Middle attacks the simplest mode can be improved by using "\fB-ssl\fR \fISAVE\fR" to have x11vnc create a longer term self-signed certificate, and then (safely) copy the corresponding public key cert to the desired client machines (care must be taken the private key part is not stolen; you will be prompted for a passphrase). .IP So keep in mind no CA key creation or management (-sslGenCA and \fB-sslGenCert)\fR is needed for either of the above two common usage modes. .IP One might want to use \fB-sslGenCA\fR and \fB-sslGenCert\fR if you had a large number of VNC client and server workstations. That way the administrator could generate a single CA key with \fB-sslGenCA\fR and distribute its certificate part to all of the workstations. .IP Next, he could create signed VNC server keys (-sslGenCert server ...) for each workstation or user that then x11vnc would use to authenticate itself to any VNC client that has the CA cert. .IP Optionally, the admin could also make it so the VNC clients themselves are authenticated to x11vnc (-sslGenCert client ...) For this \fB-sslverify\fR would be pointed to the CA cert (and/or self-signed certs). .IP x11vnc will be able to use all of these cert and key files. On the VNC client side, they will need to be "imported" somehow. Web browsers have "Manage Certificates" actions as does the Java applet plugin Control Panel. stunnel can also use these files (see the ssl_vncviewer example script in the FAQ.) .PP \fB-sslGenCA\fR \fI[dir]\fR .IP Generate your own Certificate Authority private key, certificate, and other files in directory [dir]. .IP If [dir] is not supplied, a \fB-ssldir\fR setting is used, or otherwise ~/.vnc/certs is used. .IP This command also creates directories where server and client certs and keys will be stored. The .IR openssl (1) program must be installed on the system and available in PATH. .IP After the CA files and directories are created the command exits; the VNC server is not run. .IP You will be prompted for information to put into the CA certificate. The info does not have to be accurate just as long as clients accept the cert for VNC connections. You will also need to supply a passphrase of at least 4 characters for the CA private key. .IP Once you have generated the CA you can distribute its certificate part, [dir]/CA/cacert.pem, to other workstations where VNC viewers will be run. One will need to "import" this certicate in the applications, e.g. Web browser, Java applet plugin, stunnel, etc. Next, you can create and sign keys using the CA with the \fB-sslGenCert\fR option below. .IP Examples: x11vnc \fB-sslGenCA\fR x11vnc \fB-sslGenCA\fR ~/myCAdir x11vnc \fB-ssldir\fR ~/myCAdir \fB-sslGenCA\fR .IP (the last two lines are equivalent) .PP \fB-sslGenCert\fR \fItype\fR \fIname\fR .IP Generate a VNC server or client certificate and private key pair signed by the CA created previously with \fB-sslGenCA.\fR The .IR openssl (1) program must be installed on the system and available in PATH. .IP After the Certificate is generated the command exits; the VNC server is not run. .IP The type of key to be generated is the string \fItype\fR. It is either "server" (i.e. for use by x11vnc) or "client" (for a VNC viewer). Note that typically only "server" is used: the VNC clients authenticate themselves by a non-public-key method (e.g. VNC or unix password). \fItype\fR is required. .IP An arbitrary default name you want to associate with the key is supplied by the \fIname\fR string. You can change it at the various prompts when creating the key. \fIname\fR is optional. .IP If name is left blank for clients keys then "nobody" is used. If left blank for server keys, then the primary server key: "server.pem" is created (this is the saved one referenced by "\fB-ssl\fR \fISAVE\fR" when the server is started) .IP If \fIname\fR begins with the string "self:" then a self-signed certificate is created instead of one signed by your CA key. .IP If \fIname\fR begins with the string "req:" then only a key (.key) and a certificate signing *request* (.req) are generated. You can then send the .req file to an external CA (even a professional one, e.g. Thawte) and then combine the .key and the received cert into the .pem file with the same basename. .IP The distinction between "server" and "client" is simply the choice of output filenames and sub-directory. This makes it so the \fB-ssl\fR SAVE-name option can easily pick up the x11vnc PEM file this option generates. And similarly makes it easy for the \fB-sslverify\fR option to pick up your client certs. .IP There is nothing special about the filename or directory location of either the "server" and "client" certs. You can rename the files or move them to wherever you like. .IP Precede this option with \fB-ssldir\fR [dir] to use a directory other than the default ~/.vnc/certs You will need to run \fB-sslGenCA\fR on that directory first before doing any \fB-sslGenCert\fR key creation. .IP Note you cannot recreate a cert with exactly the same distiguished name (DN) as an existing one. To do so, you will need to edit the [dir]/CA/index.txt file to delete the line. .IP Similar to \fB-sslGenCA,\fR you will be prompted to fill in some information that will be recorded in the certificate when it is created. Tip: if you know the fully-quailified hostname other people will be connecting to you can use that as the CommonName "CN" to avoid some applications (e.g. web browsers and java plugin) complaining it does not match the hostname. .IP You will also need to supply the CA private key passphrase to unlock the private key created from \fB-sslGenCA.\fR This private key is used to sign the server or client certicate. .IP The "server" certs can be used by x11vnc directly by pointing to them via the \fB-ssl\fR [pem] option. The default file will be ~/.vnc/certs/server.pem. This one would be used by simply typing \fB-ssl\fR SAVE. The pem file contains both the certificate and the private key. server.crt file contains the cert only. .IP The "client" cert + private key file will need to be copied and imported into the VNC viewer side applications (Web browser, Java plugin, stunnel, etc.) Once that is done you can delete the "client" private key file on this machine since it is only needed on the VNC viewer side. The, e.g. ~/.vnc/certs/clients/.pem contains both the cert and private key. The .crt contains the certificate only. .IP NOTE: It is very important to know one should always generate new keys with a passphrase. Otherwise if an untrusted user steals the key file he could use it to masquerade as the x11vnc server (or VNC viewer client). You will be prompted whether to encrypt the key with a passphrase or not. It is recommended that you do. One inconvenience to a passphrase is that it must be suppled every time x11vnc or the client app is started up. .IP Examples: .IP x11vnc \fB-sslGenCert\fR server x11vnc \fB-ssl\fR SAVE \fB-display\fR :0 ... .IP and then on viewer using ssl_vncviewer stunnel wrapper (see the FAQ): ssl_vncviewer \fB-verify\fR ./cacert.crt hostname:0 .IP (this assumes the cacert.crt cert from \fB-sslGenCA\fR was safely copied to the VNC viewer machine where ssl_vncviewer is run) .IP Example using a name: .IP x11vnc \fB-sslGenCert\fR server charlie x11vnc \fB-ssl\fR SAVE-charlie \fB-display\fR :0 ... .IP Example for a client certificate (rarely used): .IP x11vnc \fB-sslGenCert\fR client roger scp ~/.vnc/certs/clients/roger.pem somehost:. rm ~/.vnc/certs/clients/roger.pem .IP x11vnc is then started with the the option \fB-sslverify\fR ~/.vnc/certs/clients/roger.crt (or simply \fB-sslverify\fR roger), and on the viewer user on somehost could do for example: .IP ssl_vncviewer \fB-mycert\fR ./roger.pem hostname:0 .PP \fB-sslEncKey\fR \fI[pem]\fR .IP Utility to encrypt an existing PEM file with a passphrase you supply when prompted. For that key to be used (e.g. by x11vnc) the passphrase must be supplied each time. .IP The "SAVE" notation described under \fB-ssl\fR applies as well. (precede this option with \fB-ssldir\fR [dir] to refer a directory besides the default ~/.vnc/certs) .IP The .IR openssl (1) program must be installed on the system and available in PATH. After the Key file is encrypted the command exits; the VNC server is not run. .IP Examples: x11vnc \fB-sslEncKey\fR /path/to/foo.pem x11vnc \fB-sslEncKey\fR SAVE x11vnc \fB-sslEncKey\fR SAVE-charlie .PP \fB-sslCertInfo\fR \fI[pem]\fR .IP Prints out information about an existing PEM file. In addition the public certificate is also printed. The .IR openssl (1) program must be in PATH. Basically the command "openssl x509 \fB-text"\fR is run on the pem. .IP The "SAVE" notation described under \fB-ssl\fR applies as well. .IP Using "LIST" will give a list of all certs being managed (in the ~/.vnc/certs dir, use \fB-ssldir\fR to refer to another dir). "ALL" will print out the info for every managed key (this can be very long). Giving a client or server cert shortname will also try a lookup (e.g. \fB-sslCertInfo\fR charlie). Use "LISTL" or "LL" for a long (ls \fB-l\fR style) listing. .IP Using "HASHON" will create subdirs [dir]/HASH and [dir]/HASH with OpenSSL hash filenames (e.g. 0d5fbbf1.0) symlinks pointing up to the corresponding *.crt file. ([dir] is ~/.vnc/certs or one given by \fB-ssldir.)\fR This is a useful way for other OpenSSL applications (e.g. stunnel) to access all of the certs without having to concatenate them. x11vnc will not use them unless you specifically reference them. "HASHOFF" removes these HASH subdirs. .IP The LIST, LISTL, LL, ALL, HASHON, HASHOFF words can also be lowercase, e.g. "list". .PP \fB-sslDelCert\fR \fI[pem]\fR .IP Prompts you to delete all .crt .pem .key .req files associated with [pem]. "SAVE" and lookups as in \fB-sslCertInfo\fR apply as well. .PP \fB-stunnel\fR \fI[pem]\fR .IP Use the .IR stunnel (8) (www.stunnel.org) to provide an encrypted SSL tunnel between viewers and x11vnc. .IP This external tunnel method was implemented prior to the integrated \fB-ssl\fR encryption described above. It still works well. This requires stunnel to be installed on the system and available via PATH (n.b. stunnel is often installed in sbin directories). Version 4.x of stunnel is assumed (but see \fB-stunnel3\fR below.) .IP [pem] is optional, use "\fB-stunnel\fR \fI/path/to/stunnel.pem\fR" to specify a PEM certificate file to pass to stunnel. Whether one is needed or not depends on your stunnel configuration. stunnel often generates one at install time. See the stunnel documentation for details. .IP stunnel is started up as a child process of x11vnc and any SSL connections stunnel receives are decrypted and sent to x11vnc over a local socket. The strings "The SSL VNC desktop is ..." and "SSLPORT=..." are printed out at startup to indicate this. .IP The \fB-localhost\fR option is enforced by default to avoid people routing around the SSL channel. Set STUNNEL_DISABLE_LOCALHOST=1 before starting x11vnc to disable the requirement. .IP Your VNC viewer will also need to be able to connect via SSL. Unfortunately not too many do this. UltraVNC has an encryption plugin but it does not seem to be SSL. .IP Also, in the x11vnc distribution, a patched TightVNC Java applet is provided in classes/ssl that does SSL connections (only). .IP It is also not too difficult to set up an stunnel or other SSL tunnel on the viewer side. A simple example on Unix using stunnel 3.x is: .IP % stunnel \fB-c\fR \fB-d\fR localhost:5901 \fB-r\fR remotehost:5900 % vncviewer localhost:1 .IP For Windows, stunnel has been ported to it and there are probably other such tools available. See the FAQ for more examples. .PP \fB-stunnel3\fR \fI[pem]\fR .IP Use version 3.x stunnel command line syntax instead of version 4.x .PP \fB-https\fR \fI[port]\fR .IP Choose a separate HTTPS port (-ssl mode only). .IP In \fB-ssl\fR mode, it turns out you can use the single VNC port (e.g. 5900) for both VNC and HTTPS connections. (HTTPS is used to retrieve a SSL-aware VncViewer.jar applet that is provided with x11vnc). Since both use SSL the implementation was extended to detect if HTTP traffic (i.e. GET) is taking place and handle it accordingly. The URL would be, e.g.: .IP https://mymachine.org:5900/ .IP This is convenient for firewalls, etc, because only one port needs to be allowed in. However, this heuristic adds a few seconds delay to each connection and can be unreliable (especially if the user takes much time to ponder the Certificate dialogs in his browser, Java VM, or VNC Viewer applet. That's right 3 separate "Are you sure you want to connect" dialogs!) .IP So use the \fB-https\fR option to provide a separate, more reliable HTTPS port that x11vnc will listen on. If [port] is not provided (or is 0), one is autoselected. The URL to use is printed out at startup. .IP The SSL Java applet directory is specified via the \fB-httpdir\fR option. If not supplied it will try to guess the directory as though the \fB-http\fR option was supplied. .PP \fB-usepw\fR .IP If no other password method was supplied on the command line, first look for ~/.vnc/passwd and if found use it with \fB-rfbauth;\fR next, look for ~/.vnc/passwdfile and use it with \fB-passwdfile;\fR otherwise, prompt the user for a password to create ~/.vnc/passwd and use it with the \fB-rfbauth\fR option. If none of these succeed x11vnc exits immediately. .IP Note: \fB-unixpw\fR currently does not count as a password method by this option. .PP \fB-storepasswd\fR \fIpass\fR \fIfile\fR .IP Store password \fIpass\fR as the VNC password in the file \fIfile\fR. Once the password is stored the program exits. Use the password via "\fB-rfbauth\fR \fIfile\fR" .IP If called with no arguments, "x11vnc \fB-storepasswd",\fR the user is prompted for a password and it is stored in the file ~/.vnc/passwd. Called with one argument, that will be the file to store the prompted password in. .PP \fB-nopw\fR .IP Disable the big warning message when you use x11vnc without some sort of password. .PP \fB-accept\fR \fIstring\fR .IP Run a command (possibly to prompt the user at the X11 display) to decide whether an incoming client should be allowed to connect or not. \fIstring\fR is an external command run via .IR system (3) or some special cases described below. Be sure to quote \fIstring\fR if it contains spaces, shell characters, etc. If the external command returns 0 the client is accepted, otherwise the client is rejected. See below for an extension to accept a client view-only. .IP If x11vnc is running as root (say from .IR inetd (1) or from display managers .IR xdm (1) , .IR gdm (1) , etc), think about the security implications carefully before supplying this option (likewise for the \fB-gone\fR option). .IP Environment: The RFB_CLIENT_IP environment variable will be set to the incoming client IP number and the port in RFB_CLIENT_PORT (or -1 if unavailable). Similarly, RFB_SERVER_IP and RFB_SERVER_PORT (the x11vnc side of the connection), are set to allow identification of the tcp virtual circuit. The x11vnc process id will be in RFB_X11VNC_PID, a client id number in RFB_CLIENT_ID, and the number of other connected clients in RFB_CLIENT_COUNT. RFB_MODE will be "accept". RFB_STATE will be PROTOCOL_VERSION, SECURITY_TYPE, AUTHENTICATION, INITIALISATION, NORMAL, or UNKNOWN indicating up to which state the client has acheived. RFB_LOGIN_VIEWONLY will be 0, 1, or -1 (unknown). RFB_USERNAME, RFB_LOGIN_TIME, and RFB_CURRENT_TIME may also be set. .IP If \fIstring\fR is "popup" then a builtin popup window is used. The popup will time out after 120 seconds, use "popup:N" to modify the timeout to N seconds (use 0 for no timeout). .IP If \fIstring\fR is "xmessage" then an .IR xmessage (1) invocation is used for the command. xmessage must be installed on the machine for this to work. .IP Both "popup" and "xmessage" will present an option for accepting the client "View-Only" (the client can only watch). This option will not be presented if \fB-viewonly\fR has been specified, in which case the entire display is view only. .IP If the user supplied command is prefixed with something like "yes:0,no:*,view:3 mycommand ..." then this associates the numerical command return code with the actions: accept, reject, and accept-view-only, respectively. Use "*" instead of a number to indicate the default action (in case the command returns an unexpected value). E.g. "no:*" is a good choice. .IP Note that x11vnc blocks while the external command or popup is running (other clients may see no updates during this period). So a person sitting a the physical display is needed to respond to an popup prompt. (use a 2nd x11vnc if you lock yourself out). .IP More \fB-accept\fR tricks: use "popupmouse" to only allow mouse clicks in the builtin popup to be recognized. Similarly use "popupkey" to only recognize keystroke responses. These are to help avoid the user accidentally accepting a client by typing or clicking. All 3 of the popup keywords can be followed by +N+M to supply a position for the popup window. The default is to center the popup window. .PP \fB-afteraccept\fR \fIstring\fR .IP As \fB-accept,\fR except to run a user supplied command after a client has been accepted and authenticated. RFB_MODE will be set to "afteraccept" and the other RFB_* variables are as in \fB-accept.\fR Unlike \fB-accept,\fR the command return code is not interpreted by x11vnc. Example: \fB-afteraccept\fR 'killall xlock &' .PP \fB-gone\fR \fIstring\fR .IP As \fB-accept,\fR except to run a user supplied command when a client goes away (disconnects). RFB_MODE will be set to "gone" and the other RFB_* variables are as in \fB-accept.\fR The "popup" actions apply as well. Unlike \fB-accept,\fR the command return code is not interpreted by x11vnc. Example: \fB-gone\fR 'xlock &' .PP \fB-users\fR \fIlist\fR .IP If x11vnc is started as root (say from .IR inetd (1) or from display managers .IR xdm (1) , .IR gdm (1) , etc), then as soon as possible after connections to the X display are established try to switch to one of the users in the comma separated \fIlist\fR. If x11vnc is not running as root this option is ignored. .IP Why use this option? In general it is not needed since x11vnc is already connected to the X display and can perform its primary functions. The option was added to make some of the *external* utility commands x11vnc occasionally runs work properly. In particular under GNOME and KDE to implement the "\fB-solid\fR \fIcolor\fR" feature external commands (gconftool-2 and dcop) must be run as the user owning the desktop session. Since this option switches userid it also affects the userid used to run the processes for the \fB-accept\fR and \fB-gone\fR options. It also affects the ability to read files for options such as \fB-connect,\fR \fB-allow,\fR and \fB-remap.\fR Note that the \fB-connect\fR file is also sometimes written to. .IP So be careful with this option since in many situations its use can decrease security. .IP The switch to a user will only take place if the display can still be successfully opened as that user (this is primarily to try to guess the actual owner of the session). Example: "\fB-users\fR \fIfred,wilma,betty\fR". Note that a malicious user "barney" by quickly using "xhost +" when logging in may get x11vnc to switch to user "fred". What happens next? .IP Under display managers it may be a long time before the switch succeeds (i.e. a user logs in). To make it switch immediately regardless if the display can be reopened prefix the username with the "+" character. E.g. "\fB-users\fR \fI+bob\fR" or "\fB-users\fR \fI+nobody\fR". The latter (i.e. switching immediately to user "nobody") is probably the only use of this option that increases security. .IP To immediately switch to a user *before* connections to the X display are made or any files opened use the "=" character: "\fB-users\fR \fI=bob\fR". That user needs to be able to open the X display of course. .IP The special user "guess=" means to examine the utmpx database (see .IR who (1) ) looking for a user attached to the display number (from DISPLAY or \fB-display\fR option) and try him/her. To limit the list of guesses, use: "\fB-users\fR \fIguess=bob,betty\fR". .IP Even more sinister is the special user "lurk=" that means to try to guess the DISPLAY from the utmpx login database as well. So it "lurks" waiting for anyone to log into an X session and then connects to it. Specify a list of users after the = to limit which users will be tried. To enable a different searching mode, if the first user in the list is something like ":0" or ":0-2" that indicates a range of DISPLAY numbers that will be tried (regardless of whether they are in the utmpx database) for all users that are logged in. Examples: "\fB-users\fR \fIlurk=\fR" and also "\fB-users\fR \fIlurk=:0-1,bob,mary\fR" .IP Be especially careful using the "guess=" and "lurk=" modes. They are not recommended for use on machines with untrustworthy local users. .PP \fB-noshm\fR .IP Do not use the MIT-SHM extension for the polling. Remote displays can be polled this way: be careful this can use large amounts of network bandwidth. This is also of use if the local machine has a limited number of shm segments and \fB-onetile\fR is not sufficient. .PP \fB-flipbyteorder\fR .IP Sometimes needed if remotely polled host has different endianness. Ignored unless \fB-noshm\fR is set. .PP \fB-onetile\fR .IP Do not use the new copy_tiles() framebuffer mechanism, just use 1 shm tile for polling. Limits shm segments used to 3. .PP \fB-solid\fR \fI[color]\fR .IP To improve performance, when VNC clients are connected try to change the desktop background to a solid color. The [color] is optional: the default color is "cyan4". For a different one specify the X color (rgb.txt name, e.g. "darkblue" or numerical "#RRGGBB"). .IP Currently this option only works on GNOME, KDE, CDE, and classic X (i.e. with the background image on the root window). The "gconftool-2" and "dcop" external commands are run for GNOME and KDE respectively. Other desktops won't work, e.g. Xfce (send us the corresponding commands if you find them). If x11vnc is running as root ( .IR inetd (1) or .IR gdm (1) ), the \fB-users\fR option may be needed for GNOME and KDE. If x11vnc guesses your desktop incorrectly, you can force it by prefixing color with "gnome:", "kde:", "cde:" or "root:". .PP \fB-blackout\fR \fIstring\fR .IP Black out rectangles on the screen. \fIstring\fR is a comma separated list of WxH+X+Y type geometries for each rectangle. If one of the items on the list is the string "noptr" the mouse pointer will not be allowed to go into a blacked out region. .PP \fB-xinerama,\fR \fB-noxinerama\fR .IP If your screen is composed of multiple monitors glued together via XINERAMA, and that screen is not a rectangle this option will try to guess the areas to black out (if your system has libXinerama). default: \fB-xinerama\fR .IP In general, we have noticed on XINERAMA displays you may need to use the "\fB-xwarppointer\fR" option if the mouse pointer misbehaves. .PP \fB-xtrap\fR .IP Use the DEC-XTRAP extension for keystroke and mouse input insertion. For use on legacy systems, e.g. X11R5, running an incomplete or missing XTEST extension. By default DEC-XTRAP will be used if XTEST server grab control is missing, use \fB-xtrap\fR to do the keystroke and mouse insertion via DEC-XTRAP as well. .PP \fB-xrandr\fR \fI[mode]\fR .IP If the display supports the XRANDR (X Resize, Rotate and Reflection) extension, and you expect XRANDR events to occur to the display while x11vnc is running, this options indicates x11vnc should try to respond to them (as opposed to simply crashing by assuming the old screen size). See the .IR xrandr (1) manpage and run \'xrandr \fB-q'\fR for more info. [mode] is optional and described below. .IP Since watching for XRANDR events and trapping errors increases polling overhead, only use this option if XRANDR changes are expected. For example on a rotatable screen PDA or laptop, or using a XRANDR-aware Desktop where you resize often. It is best to be viewing with a vncviewer that supports the NewFBSize encoding, since it knows how to react to screen size changes. Otherwise, libvncserver tries to do so something reasonable for viewers that cannot do this (portions of the screen may be clipped, unused, etc). .IP "mode" defaults to "resize", which means create a new, resized, framebuffer and hope all viewers can cope with the change. "newfbsize" means first disconnect all viewers that do not support the NewFBSize VNC encoding, and then resize the framebuffer. "exit" means disconnect all viewer clients, and then terminate x11vnc. .PP \fB-padgeom\fR \fIWxH\fR .IP Whenever a new vncviewer connects, the framebuffer is replaced with a fake, solid black one of geometry WxH. Shortly afterwards the framebuffer is replaced with the real one. This is intended for use with vncviewers that do not support NewFBSize and one wants to make sure the initial viewer geometry will be big enough to handle all subsequent resizes (e.g. under \fB-xrandr,\fR \fB-remote\fR id:windowid, rescaling, etc.) .PP \fB-o\fR \fIlogfile\fR .IP Write stderr messages to file \fIlogfile\fR instead of to the terminal. Same as "\fB-logfile\fR \fIfile\fR". To append to the file use "\fB-oa\fR \fIfile\fR" or "\fB-logappend\fR \fIfile\fR". .PP \fB-flag\fR \fIfile\fR .IP Write the "PORT=NNNN" (e.g. PORT=5900) string to \fIfile\fR in addition to stdout. This option could be useful by wrapper script to detect when x11vnc is ready. .PP \fB-rc\fR \fIfilename\fR .IP Use \fIfilename\fR instead of $HOME/.x11vncrc for rc file. .PP \fB-norc\fR .IP Do not process any .x11vncrc file for options. .PP \fB-h,\fR \fB-help\fR .IP Print this help text. -?, \fB-opts\fR Only list the x11vnc options. .PP \fB-V,\fR \fB-version\fR .IP Print program version and last modification date. .PP \fB-dbg\fR .IP Instead of exiting after cleaning up, run a simple "debug crash shell" when fatal errors are trapped. .PP \fB-q\fR .IP Be quiet by printing less informational output to stderr. Same as \fB-quiet.\fR .PP \fB-bg\fR .IP Go into the background after screen setup. Messages to stderr are lost unless \fB-o\fR logfile is used. Something like this could be useful in a script: .IP port=`ssh $host "x11vnc -display :0 -bg" | grep PORT` .IP port=`echo "$port" | sed -e 's/PORT=//'` .IP port=`expr $port - 5900` .IP vncviewer $host:$port .PP \fB-modtweak,\fR \fB-nomodtweak\fR .IP Option \fB-modtweak\fR automatically tries to adjust the AltGr and Shift modifiers for differing language keyboards between client and host. Otherwise, only a single key press/release of a Keycode is simulated (i.e. ignoring the state of the modifiers: this usually works for identical keyboards). Also useful in resolving cases where a Keysym is bound to multiple keys (e.g. "<" + ">" and "," + "<" keys). Default: \fB-modtweak\fR .PP \fB-xkb,\fR \fB-noxkb\fR .IP When in modtweak mode, use the XKEYBOARD extension (if the X display supports it) to do the modifier tweaking. This is powerful and should be tried if there are still keymapping problems when using \fB-modtweak\fR by itself. The default is to check whether some common keysyms, e.g. !, @, [, are only accessible via \fB-xkb\fR mode and if so then automatically enable the mode. To disable this automatic detection use \fB-noxkb.\fR .PP \fB-skip_keycodes\fR \fIstring\fR .IP Ignore the comma separated list of decimal keycodes. Perhaps these are keycodes not on your keyboard but your X server thinks exist. Currently only applies to \fB-xkb\fR mode. Use this option to help x11vnc in the reverse problem it tries to solve: Keysym -> Keycode(s) when ambiguities exist (more than one Keycode per Keysym). Run 'xmodmap \fB-pk'\fR to see your keymapping. Example: "\fB-skip_keycodes\fR \fI94,114\fR" .PP \fB-sloppy_keys\fR .IP Experimental option that tries to correct some "sloppy" key behavior. E.g. if at the viewer you press Shift+Key but then release the Shift before Key that could give rise to extra unwanted characters (usually only between keyboards of different languages). Only use this option if you observe problems with some keystrokes. .PP \fB-skip_dups,\fR \fB-noskip_dups\fR .IP Some VNC viewers send impossible repeated key events, e.g. key-down, key-down, key-up, key-up all for the same key, or 20 downs in a row for the same modifier key! Setting \fB-skip_dups\fR means to skip these duplicates and just process the first event. Note: some VNC viewers assume they can send down's without the corresponding up's and so you should not set this option for these viewers (symptom: some keys do not autorepeat) Default: \fB-noskip_dups\fR .PP \fB-add_keysyms,\fR \fB-noadd_keysyms\fR .IP If a Keysym is received from a VNC viewer and that Keysym does not exist in the X server, then add the Keysym to the X server's keyboard mapping on an unused key. Added Keysyms will be removed periodically and also when x11vnc exits. Default: \fB-add_keysyms\fR .PP \fB-clear_mods\fR .IP At startup and exit clear the modifier keys by sending KeyRelease for each one. The Lock modifiers are skipped. Used to clear the state if the display was accidentally left with any pressed down. .PP \fB-clear_keys\fR .IP As \fB-clear_mods,\fR except try to release any pressed key. Note that this option and \fB-clear_mods\fR can interfere with a person typing at the physical keyboard. .PP \fB-remap\fR \fIstring\fR .IP Read Keysym remappings from file named \fIstring\fR. Format is one pair of Keysyms per line (can be name or hex value) separated by a space. If no file named \fIstring\fR exists, it is instead interpreted as this form: key1-key2,key3-key4,... See header file for a list of Keysym names, or use .IR xev (1). To map a key to a button click, use the fake Keysyms "Button1", ..., etc. E.g: "\fB-remap\fR \fISuper_R-Button2\fR" (useful for pasting on a laptop) .IP Dead keys: "dead" (or silent, mute) keys are keys that do not produce a character but must be followed by a 2nd keystroke. This is often used for accenting characters, e.g. to put "`" on top of "a" by pressing the dead key and then "a". Note that this interpretation is not part of core X11, it is up to the toolkit or application to decide how to react to the sequence. The X11 names for these keysyms are "dead_grave", "dead_acute", etc. However some VNC viewers send the keysyms "grave", "acute" instead thereby disabling the accenting. To work around this \fB-remap\fR can be used. For example "\fB-remap\fR \fIgrave-dead_grave,acute-dead_acute\fR" .IP As a convenience, "\fB-remap\fR \fIDEAD\fR" applies these remaps: .IP g grave-dead_grave a acute-dead_acute c asciicircum-dead_circumflex t asciitilde-dead_tilde m macron-dead_macron b breve-dead_breve D abovedot-dead_abovedot d diaeresis-dead_diaeresis o degree-dead_abovering A doubleacute-dead_doubleacute r caron-dead_caron e cedilla-dead_cedilla .IP .IP If you just want a subset use the first letter label, e.g. "\fB-remap\fR \fIDEAD=ga\fR" to get the first two. Additional remaps may also be supplied via commas, e.g. "\fB-remap\fR \fIDEAD=ga,Super_R-Button2\fR". Finally, "DEAD=missing" means to apply all of the above as long as the left hand member is not already in the X11 keymap. .PP \fB-norepeat,\fR \fB-repeat\fR .IP Option \fB-norepeat\fR disables X server key auto repeat when VNC clients are connected and VNC keyboard input is not idle for more than 5 minutes. This works around a repeating keystrokes bug (triggered by long processing delays between key down and key up client events: either from large screen changes or high latency). Default: \fB-norepeat\fR .IP Note: your VNC viewer side will likely do autorepeating, so this is no loss unless someone is simultaneously at the real X display. .IP Use "\fB-norepeat\fR \fIN\fR" to set how many times norepeat will be reset if something else (e.g. X session manager) undoes it. The default is 2. Use a negative value for unlimited resets. .PP \fB-nofb\fR .IP Ignore video framebuffer: only process keyboard and pointer. Intended for use with Win2VNC and x2vnc dual-monitor setups. .PP \fB-nobell\fR .IP Do not watch for XBell events. (no beeps will be heard) Note: XBell monitoring requires the XKEYBOARD extension. .PP \fB-nosel\fR .IP Do not manage exchange of X selection/cutbuffer between VNC viewers and the X server at all. .PP \fB-noprimary\fR .IP Do not poll the PRIMARY selection for changes to send back to clients. (PRIMARY is still set on received changes, however). .PP \fB-nosetprimary\fR .IP Do not set the PRIMARY selection for changes received from VNC clients. .PP \fB-noclipboard\fR .IP Do not poll the CLIPBOARD selection for changes to send back to clients. (CLIPBOARD is still set on received changes, however). .PP \fB-nosetclipboard\fR .IP Do not set the CLIPBOARD selection for changes received from VNC clients. .PP \fB-seldir\fR \fIstring\fR .IP If direction string is "send", only send the selection to viewers, and if it is "recv" only receive it from viewers. To work around apps setting the selection too frequently and messing up the other end. You can actually supply a comma separated list of directions, including "debug" to turn on debugging output. .PP \fB-cursor\fR \fI[mode],\fR \fB-nocursor\fR .IP Sets how the pointer cursor shape (little icon at the mouse pointer) should be handled. The "mode" string is optional and is described below. The default is to show some sort of cursor shape(s). How this is done depends on the VNC viewer and the X server. Use \fB-nocursor\fR to disable cursor shapes completely. .IP Some VNC viewers support the TightVNC CursorPosUpdates and CursorShapeUpdates extensions (cuts down on network traffic by not having to send the cursor image every time the pointer is moved), in which case these extensions are used (see \fB-nocursorshape\fR and \fB-nocursorpos\fR below to disable). For other viewers the cursor shape is written directly to the framebuffer every time the pointer is moved or changed and gets sent along with the other framebuffer updates. In this case, there will be some lag between the vnc viewer pointer and the remote cursor position. .IP If the X display supports retrieving the cursor shape information from the X server, then the default is to use that mode. On Solaris this can be done with the SUN_OVL extension using \fB-overlay\fR (see also the \fB-overlay_nocursor\fR option). A similar overlay scheme is used on IRIX. Xorg (e.g. Linux) and recent Solaris Xsun servers support the XFIXES extension to retrieve the exact cursor shape from the X server. If XFIXES is present it is preferred over Overlay and is used by default (see \fB-noxfixes\fR below). This can be disabled with \fB-nocursor,\fR and also some values of the "mode" option below. .IP Note that under XFIXES cursors with transparency (alpha channel) will usually not be exactly represented and one may find Overlay preferable. See also the \fB-alphacut\fR and \fB-alphafrac\fR options below as fudge factors to try to improve the situation for cursors with transparency for a given theme. .IP The "mode" string can be used to fine-tune the displaying of cursor shapes. It can be used the following ways: .IP "\fB-cursor\fR \fIarrow\fR" - just show the standard arrow nothing more or nothing less. .IP "\fB-cursor\fR \fInone\fR" - same as "\fB-nocursor\fR" .IP "\fB-cursor\fR \fIX\fR" - when the cursor appears to be on the root window, draw the familiar X shape. Some desktops such as GNOME cover up the root window completely, and so this will not work, try "X1", etc, to try to shift the tree depth. On high latency links or slow machines there will be a time lag between expected and the actual cursor shape. .IP "\fB-cursor\fR \fIsome\fR" - like "X" but use additional heuristics to try to guess if the window should have a windowmanager-like resizer cursor or a text input I-beam cursor. This is a complete hack, but may be useful in some situations because it provides a little more feedback about the cursor shape. .IP "\fB-cursor\fR \fImost\fR" - try to show as many cursors as possible. Often this will only be the same as "some" unless the display has overlay visuals or XFIXES extensions available. On Solaris and IRIX if XFIXES is not available, \fB-overlay\fR mode will be attempted. .PP \fB-arrow\fR \fIn\fR .IP Choose an alternate "arrow" cursor from a set of some common ones. n can be 1 to 6. Default is: 1 Ignored when in XFIXES cursor-grabbing mode. .PP \fB-noxfixes\fR .IP Do not use the XFIXES extension to draw the exact cursor shape even if it is available. .PP \fB-alphacut\fR \fIn\fR .IP When using the XFIXES extension for the cursor shape, cursors with transparency will not usually be displayed exactly (but opaque ones will). This option sets n as a cutoff for cursors that have transparency ("alpha channel" with values ranging from 0 to 255) Any cursor pixel with alpha value less than n becomes completely transparent. Otherwise the pixel is completely opaque. Default 240 .PP \fB-alphafrac\fR \fIfraction\fR .IP With the threshold in \fB-alphacut\fR some cursors will become almost completely transparent because their alpha values are not high enough. For those cursors adjust the alpha threshold until fraction of the non-zero alpha channel pixels become opaque. Default 0.33 .PP \fB-alpharemove\fR .IP By default, XFIXES cursors pixels with transparency have the alpha factor multiplied into the RGB color values (i.e. that corresponding to blending the cursor with a black background). Specify this option to remove the alpha factor. (useful for light colored semi-transparent cursors). .PP \fB-noalphablend\fR .IP In XFIXES mode do not send cursor alpha channel data to libvncserver. The default is to send it. The alphablend effect will only be visible in \fB-nocursorshape\fR mode or for clients with cursorshapeupdates turned off. (However there is a hack for 32bpp with depth 24, it uses the extra 8 bits to store cursor transparency for use with a hacked vncviewer that applies the transparency locally. See the FAQ for more info). .PP \fB-nocursorshape\fR .IP Do not use the TightVNC CursorShapeUpdates extension even if clients support it. See \fB-cursor\fR above. .PP \fB-cursorpos,\fR \fB-nocursorpos\fR .IP Option \fB-cursorpos\fR enables sending the X cursor position back to all vnc clients that support the TightVNC CursorPosUpdates extension. Other clients will be able to see the pointer motions. Default: \fB-cursorpos\fR .PP \fB-xwarppointer\fR .IP Move the pointer with .IR XWarpPointer (3X) instead of the XTEST extension. Use this as a workaround if the pointer motion behaves incorrectly, e.g. on touchscreens or other non-standard setups. Also sometimes needed on XINERAMA displays. .PP \fB-buttonmap\fR \fIstring\fR .IP String to remap mouse buttons. Format: IJK-LMN, this maps buttons I -> L, etc., e.g. \fB-buttonmap\fR 13-31 .IP Button presses can also be mapped to keystrokes: replace a button digit on the right of the dash with :: or :+: etc. for multiple keys. For example, if the viewing machine has a mouse-wheel (buttons 4 5) but the x11vnc side does not, these will do scrolls: .IP \fB-buttonmap\fR 12345-123:Prior::Next: .IP \fB-buttonmap\fR 12345-123:Up+Up+Up::Down+Down+Down: .IP See header file for a list of Keysyms, or use the .IR xev (1) program. Note: mapping of button clicks to Keysyms may not work if \fB-modtweak\fR or \fB-xkb\fR is needed for the Keysym. .IP If you include a modifier like "Shift_L" the modifier's up/down state is toggled, e.g. to send "The" use :Shift_L+t+Shift_L+h+e: (the 1st one is shift down and the 2nd one is shift up). (note: the initial state of the modifier is ignored and not reset) To include button events use "Button1", ... etc. .PP \fB-nodragging\fR .IP Do not update the display during mouse dragging events (mouse button held down). Greatly improves response on slow setups, but you lose all visual feedback for drags, text selection, and some menu traversals. It overrides any \fB-pointer_mode\fR setting. .PP \fB-wireframe\fR \fI[str],\fR \fB-nowireframe\fR .IP Try to detect window moves or resizes when a mouse button is held down and show a wireframe instead of the full opaque window. This is based completely on heuristics and may not always work: it depends on your window manager and even how you move things around. See \fB-pointer_mode\fR below for discussion of the "bogging down" problem this tries to avoid. Default: \fB-wireframe\fR .IP Shorter aliases: \fB-wf\fR [str] and \fB-nowf\fR .IP The value "str" is optional and, of course, is packed with many tunable parameters for this scheme: .IP Format: shade,linewidth,percent,T+B+L+R,mod,t1+t2+t3+t4 Default: 0xff,3,0,32+8+8+8,all,0.15+0.30+5.0+0.125 .IP If you leave nothing between commas: ",," the default value is used. If you don't specify enough commas, the trailing parameters are set to their defaults. .IP "shade" indicate the "color" for the wireframe, usually a greyscale: 0-255, however for 16 and 32bpp you can specify an rgb.txt X color (e.g. "dodgerblue") or a value > 255 is treated as RGB (e.g. red is 0xff0000). "linewidth" sets the width of the wireframe in pixels. "percent" indicates to not apply the wireframe scheme to windows with area less than this percent of the full screen. .IP "T+B+L+R" indicates four integers for how close in pixels the pointer has to be from the Top, Bottom, Left, or Right edges of the window to consider wireframing. This is a speedup to quickly exclude a window from being wireframed: set them all to zero to not try the speedup (scrolling and selecting text will likely be slower). .IP "mod" specifies if a button down event in the interior of the window with a modifier key (Alt, Shift, etc.) down should indicate a wireframe opportunity. It can be "0" or "none" to skip it, "1" or "all" to apply it to any modifier, or "Shift", "Alt", "Control", "Meta", "Super", or "Hyper" to only apply for that type of modifier key. .IP "t1+t2+t3+t4" specify four floating point times in seconds: t1 is how long to wait for the pointer to move, t2 is how long to wait for the window to start moving or being resized (for some window managers this can be rather long), t3 is how long to keep a wireframe moving before repainting the window. t4 is the minimum time between sending wireframe "animations". If a slow link is detected, these values may be automatically changed to something better for a slow link. .PP \fB-wirecopyrect\fR \fImode,\fR \fB-nowirecopyrect\fR .IP Since the \fB-wireframe\fR mechanism evidently tracks moving windows accurately, a speedup can be obtained by telling the VNC viewers to locally copy the translated window region. This is the VNC CopyRect encoding: the framebuffer update doesn't need to send the actual new image data. .IP Shorter aliases: \fB-wcr\fR [mode] and \fB-nowcr\fR .IP "mode" can be "never" (same as \fB-nowirecopyrect)\fR to never try the copyrect, "top" means only do it if the window was not covered by any other windows, and "always" means to translate the orginally unobscured region (this may look odd as the remaining pieces come in, but helps on a slow link). Default: "always" .IP Note: there can be painting errors or slow response when using \fB-scale\fR so you may want to disable CopyRect in this case "\fB-wirecopyrect\fR \fInever\fR" on the command line or by remote-control. Or you can also use the "\fB-scale\fR \fIxxx:nocr\fR" scale option. .PP \fB-debug_wireframe\fR .IP Turn on debugging info printout for the wireframe heuristics. "\fB-dwf\fR" is an alias. Specify multiple times for more output. .PP \fB-scrollcopyrect\fR \fImode,\fR \fB-noscrollcopyrect\fR .IP Like \fB-wirecopyrect,\fR but use heuristics to try to guess if a window has scrolled its contents (either vertically or horizontally). This requires the RECORD X extension to "snoop" on X applications (currently for certain XCopyArea and XConfigureWindow X protocol requests). Examples: Hitting in a terminal window when the cursor was at the bottom, the text scrolls up one line. Hitting arrow in a web browser window, the web page scrolls up a small amount. Or scrolling with a scrollbar or mouse wheel. .IP Shorter aliases: \fB-scr\fR [mode] and \fB-noscr\fR .IP This scheme will not always detect scrolls, but when it does there is a nice speedup from using the VNC CopyRect encoding (see \fB-wirecopyrect).\fR The speedup is both in reduced network traffic and reduced X framebuffer polling/copying. On the other hand, it may induce undesired transients (e.g. a terminal cursor being scrolled up when it should not be) or other painting errors (window tearing, bunching-up, etc). These are automatically repaired in a short period of time. If this is unacceptable disable the feature with \fB-noscrollcopyrect.\fR .IP Screen clearing kludges: for testing at least, there are some "magic key sequences" (must be done in less than 1 second) to aid repairing painting errors that may be seen when using this mode: .IP 3 Alt_L's in a row: resend whole screen, 4 Alt_L's in a row: reread and resend whole screen, 3 Super_L's in a row: mark whole screen for polling, 4 Super_L's in a row: reset RECORD context, 5 Super_L's in a row: try to push a black screen .IP note: Alt_L is the Left "Alt" key (a single key) Super_L is the Left "Super" key (Windows flag). Both of these are modifier keys, and so should not generate characters when pressed by themselves. Also, your VNC viewer may have its own refresh hot-key or button. .IP "mode" can be "never" (same as \fB-noscrollcopyrect)\fR to never try the copyrect, "keys" means to try it in response to keystrokes only, "mouse" means to try it in response to mouse events only, "always" means to do both. Default: "always" .IP Note: there can be painting errors or slow response when using \fB-scale\fR so you may want to disable CopyRect in this case "\fB-scrollcopyrect\fR \fInever\fR" on the command line or by remote-control. Or you can also use the "\fB-scale\fR \fIxxx:nocr\fR" scale option. .PP \fB-scr_area\fR \fIn\fR .IP Set the minimum area in pixels for a rectangle to be considered for the \fB-scrollcopyrect\fR detection scheme. This is to avoid wasting the effort on small rectangles that would be quickly updated the normal way. E.g. suppose an app updated the position of its skinny scrollbar first and then shifted the large panel it controlled. We want to be sure to skip the small scrollbar and get the large panel. Default: 60000 .PP \fB-scr_skip\fR \fIlist\fR .IP Skip scroll detection for applications matching the comma separated list of strings in \fIlist\fR. Some applications implement their scrolling in strange ways where the XCopyArea, etc, also applies to invisible portions of the window: if we CopyRect those areas it looks awful during the scroll and there may be painting errors left after the scroll. Soffice.bin is the worst known offender. .IP Use "##" to denote the start of the application class (e.g. "##XTerm") and "++" to denote the start of the application instance name (e.g. "++xterm"). The string your list is matched against is of the form "^^WM_NAME##Class++Instance" The "xlsclients \fB-la"\fR command will provide this info. .IP If a pattern is prefixed with "KEY:" it only applies to Keystroke generated scrolls (e.g. Up arrow). If it is prefixed with "MOUSE:" it only applies to Mouse induced scrolls (e.g. dragging on a scrollbar). Default: ##Soffice.bin,##StarOffice .PP \fB-scr_inc\fR \fIlist\fR .IP Opposite of \fB-scr_skip:\fR this list is consulted first and if there is a match the window will be monitored via RECORD for scrolls irrespective of \fB-scr_skip.\fR Use \fB-scr_skip\fR '*' to skip anything that does not match your \fB-scr_inc.\fR Use \fB-scr_inc\fR '*' to include everything. .PP \fB-scr_keys\fR \fIlist\fR .IP For keystroke scroll detection, only apply the RECORD heuristics to the comma separated list of keysyms in \fIlist\fR. You may find the RECORD overhead for every one of your keystrokes disrupts typing too much, but you don't want to turn it off completely with "\fB-scr\fR \fImouse\fR" and \fB-scr_parms\fR does not work or is too confusing. .IP The listed keysyms can be numeric or the keysym names in the header file or from the .IR xev (1) program. Example: "\fB-scr_keys\fR \fIUp,Down,Return\fR". One probably wants to have application specific lists (e.g. for terminals, etc) but that is too icky to think about for now... .IP If \fIlist\fR begins with the "-" character the list is taken as an exclude list: all keysyms except those list will be considered. The special string "builtin" expands to an internal list of keysyms that are likely to cause scrolls. BTW, by default modifier keys, Shift_L, Control_R, etc, are skipped since they almost never induce scrolling by themselves. .PP \fB-scr_term\fR \fIlist\fR .IP Yet another cosmetic kludge. Apply shell/terminal heuristics to applications matching comma separated list (same as for \fB-scr_skip/-scr_inc).\fR For example an annoying transient under scroll detection is if you hit Enter in a terminal shell with full text window, the solid text cursor block will be scrolled up. So for a short time there are two (or more) block cursors on the screen. There are similar scenarios, (e.g. an output line is duplicated). .IP These transients are induced by the approximation of scroll detection (e.g. it detects the scroll, but not the fact that the block cursor was cleared just before the scroll). In nearly all cases these transient errors are repaired when the true X framebuffer is consulted by the normal polling. But they are distracting, so what this option provides is extra "padding" near the bottom of the terminal window: a few extra lines near the bottom will not be scrolled, but rather updated from the actual X framebuffer. This usually reduces the annoying artifacts. Use "none" to disable. Default: "term" .PP \fB-scr_keyrepeat\fR \fIlo-hi\fR .IP If a key is held down (or otherwise repeats rapidly) and this induces a rapid sequence of scrolls (e.g. holding down an Arrow key) the "scrollcopyrect" detection and overhead may not be able to keep up. A time per single scroll estimate is performed and if that estimate predicts a sustainable scrollrate of keys per second between "lo" and "hi" then repeated keys will be DISCARDED to maintain the scrollrate. For example your key autorepeat may be 25 keys/sec, but for a large window or slow link only 8 scrolls per second can be sustained, then roughly 2 out of every 3 repeated keys will be discarded during this period. Default: "4-20" .PP \fB-scr_parms\fR \fIstring\fR .IP Set various parameters for the scrollcopyrect mode. The format is similar to that for \fB-wireframe\fR and packed with lots of parameters: .IP Format: T+B+L+R,t1+t2+t3,s1+s2+s3+s4+s5 Default: 0+64+32+32,0.02+0.10+0.9,0.03+0.06+0.5+0.1+5.0 .IP If you leave nothing between commas: ",," the default value is used. If you don't specify enough commas, the trailing parameters are set to their defaults. .IP "T+B+L+R" indicates four integers for how close in pixels the pointer has to be from the Top, Bottom, Left, or Right edges of the window to consider scrollcopyrect. If \fB-wireframe\fR overlaps it takes precedence. This is a speedup to quickly exclude a window from being watched for scrollcopyrect: set them all to zero to not try the speedup (things like selecting text will likely be slower). .IP "t1+t2+t3" specify three floating point times in seconds that apply to scrollcopyrect detection with *Keystroke* input: t1 is how long to wait after a key is pressed for the first scroll, t2 is how long to keep looking after a Keystroke scroll for more scrolls. t3 is how frequently to try to update surrounding scrollbars outside of the scrolling area (0.0 to disable) .IP "s1+s2+s3+s4+s5" specify five floating point times in seconds that apply to scrollcopyrect detection with *Mouse* input: s1 is how long to wait after a mouse button is pressed for the first scroll, s2 is how long to keep waiting for additional scrolls after the first Mouse scroll was detected. s3 is how frequently to try to update surrounding scrollbars outside of the scrolling area (0.0 to disable). s4 is how long to buffer pointer motion (to try to get fewer, bigger mouse scrolls). s5 is the maximum time to spend just updating the scroll window without updating the rest of the screen. .PP \fB-fixscreen\fR \fIstring\fR .IP Periodically "repair" the screen based on settings in \fIstring\fR. Hopefully you won't need this option, it is intended for cases when the \fB-scrollcopyrect\fR or \fB-wirecopyrect\fR features leave too many painting errors, but it can be used for any scenario. This option periodically performs costly operations and so interactive response may be reduced when it is on. You can use 3 Alt_L's (the Left "Alt" key) taps in a row (as described under \fB-scrollcopyrect)\fR instead to manually request a screen repaint when it is needed. .IP \fIstring\fR is a comma separated list of one or more of the following: "V=t", "C=t", "X=t", and "8=t". In these "t" stands for a time in seconds (it is a floating point even though one should usually use values > 2 to avoid wasting resources). V sets how frequently the entire screen should be sent to viewers (it is like the 3 Alt_L's). C sets how long to wait after a CopyRect to repaint the full screen. X sets how frequently to reread the full X11 framebuffer from the X server and push it out to connected viewers. Use of X should be rare, please report a bug if you find you need it. 8= applies only for \fB-8to24\fR mode: it sets how often the non-default visual regions of the screen (e.g. 8bpp windows) are refreshed. Examples: \fB-fixscreen\fR V=10 \fB-fixscreen\fR C=10 .PP \fB-debug_scroll\fR .IP Turn on debugging info printout for the scroll heuristics. "\fB-ds\fR" is an alias. Specify it multiple times for more output. .PP \fB-noxrecord\fR .IP Disable any use of the RECORD extension. This is currently used by the \fB-scrollcopyrect\fR scheme and to monitor X server grabs. .PP \fB-grab_buster,\fR \fB-nograb_buster\fR .IP Some of the use of the RECORD extension can leave a tiny window for XGrabServer deadlock. This is only if the whole-server grabbing application expects mouse or keyboard input before releasing the grab. It is usually a window manager that does this. x11vnc takes care to avoid the the problem, but if caught x11vnc will freeze. Without \fB-grab_buster,\fR the only solution is to go the physical display and give it some input to satisfy the grabbing app. Or manually kill and restart the window manager if that is feasible. With \fB-grab_buster,\fR x11vnc will fork a helper thread and if x11vnc appears to be stuck in a grab after a period of time (20-30 sec) then it will inject some user input: button clicks, Escape, mouse motion, etc to try to break the grab. If you experience a lot of grab deadlock, please report a bug. .PP \fB-debug_grabs\fR .IP Turn on debugging info printout with respect to XGrabServer() deadlock for \fB-scrollcopyrect__mode_.\fR .PP \fB-debug_sel\fR .IP Turn on debugging info printout with respect to PRIMARY, CLIPBOARD, and CUTBUFFER0 selections. .PP \fB-pointer_mode\fR \fIn\fR .IP Various pointer motion update schemes. "\fB-pm\fR" is an alias. The problem is pointer motion can cause rapid changes on the screen: consider the rapid changes when you drag a large window around opaquely. Neither x11vnc's screen polling and vnc compression routines nor the bandwidth to the vncviewers can keep up these rapid screen changes: everything will bog down when dragging or scrolling. So a scheme has to be used to "eat" much of that pointer input before re-polling the screen and sending out framebuffer updates. The mode number \fIn\fR can be 0 to 4 and selects one of the schemes desribed below. .IP Note that the \fB-wireframe\fR and \fB-scrollcopyrect__mode_s\fR complement \fB-pointer_mode\fR by detecting (and improving) certain periods of "rapid screen change". .IP n=0: does the same as \fB-nodragging.\fR (all screen polling is suspended if a mouse button is pressed.) .IP n=1: was the original scheme used to about Jan 2004: it basically just skips \fB-input_skip\fR keyboard or pointer events before repolling the screen. .IP n=2 is an improved scheme: by watching the current rate of input events it tries to detect if it should try to "eat" additional pointer events before continuing. .IP n=3 is basically a dynamic \fB-nodragging\fR mode: it detects when the mouse motion has paused and then refreshes the display. .IP n=4 attempts to measures network rates and latency, the video card read rate, and how many tiles have been changed on the screen. From this, it aggressively tries to push screen "frames" when it decides it has enough resources to do so. NOT FINISHED. .IP The default n is 2. Note that modes 2, 3, 4 will skip \fB-input_skip\fR keyboard events (but it will not count pointer events). Also note that these modes are not available in \fB-threads\fR mode which has its own pointer event handling mechanism. .IP To try out the different pointer modes to see which one gives the best response for your usage, it is convenient to use the remote control function, for example "x11vnc \fB-R\fR pm:4" or the tcl/tk gui (Tuning -> pointer_mode -> n). .PP \fB-input_skip\fR \fIn\fR .IP For the pointer handling when non-threaded: try to read n user input events before scanning display. n < 0 means to act as though there is always user input. Default: 10 .PP \fB-speeds\fR \fIrd,bw,lat\fR .IP x11vnc tries to estimate some speed parameters that are used to optimize scheduling (e.g. \fB-pointer_mode\fR 4, \fB-wireframe,\fR \fB-scrollcopyrect)\fR and other things. Use the \fB-speeds\fR option to set these manually. The triple \fIrd,bw,lat\fR corresponds to video h/w read rate in MB/sec, network bandwidth to clients in KB/sec, and network latency to clients in milliseconds, respectively. If a value is left blank, e.g. "-speeds ,100,15", then the internal scheme is used to estimate the empty value(s). .IP Typical PC video cards have read rates of 5-10 MB/sec. If the framebuffer is in main memory instead of video h/w (e.g. SunRay, shadowfb, dummy driver, Xvfb), the read rate may be much faster. "x11perf \fB-getimage500"\fR can be used to get a lower bound (remember to factor in the bytes per pixel). It is up to you to estimate the network bandwith and latency to clients. For the latency the .IR ping (1) command can be used. .IP For convenience there are some aliases provided, e.g. "\fB-speeds\fR \fImodem\fR". The aliases are: "modem" for 6,4,200; "dsl" for 6,100,50; and "lan" for 6,5000,1 .PP \fB-wmdt\fR \fIstring\fR .IP For some features, e.g. \fB-wireframe\fR and \fB-scrollcopyrect,\fR x11vnc has to work around issues for certain window managers or desktops (currently kde and xfce). By default it tries to guess which one, but it can guess incorrectly. Use this option to indicate which wm/dt. \fIstring\fR can be "gnome", "kde", "cde", "xfce", or "root" (classic X wm). Anything else is interpreted as "root". .PP \fB-debug_pointer\fR .IP Print debugging output for every pointer event. .PP \fB-debug_keyboard\fR .IP Print debugging output for every keyboard event. .PP Same as \fB-dp\fR and \fB-dk,\fR respectively. Use multiple times for more output. .PP \fB-defer\fR \fItime\fR .IP Time in ms to wait for updates before sending to client (deferUpdateTime) Default: 30 .PP \fB-wait\fR \fItime\fR .IP Time in ms to pause between screen polls. Used to cut down on load. Default: 30 .PP \fB-wait_ui\fR \fIfactor\fR .IP Factor by which to cut the \fB-wait\fR time if there has been recent user input (pointer or keyboard). Improves response, but increases the load whenever you are moving the mouse or typing. Default: 2.00 .PP \fB-nowait_bog\fR .IP Do not detect if the screen polling is "bogging down" and sleep more. Some activities with no user input can slow things down a lot: consider a large terminal window with a long build running in it continously streaming text output. By default x11vnc will try to detect this (3 screen polls in a row each longer than 0.25 sec with no user input), and sleep up to 1.5 secs to let things "catch up". Use this option to disable that detection. .PP \fB-slow_fb\fR \fItime\fR .IP Floating point time in seconds delay all screen polling. For special purpose usage where a low frame rate is acceptable and desirable, but you want the user input processed at the normal rate so you cannot use \fB-wait.\fR .PP \fB-readtimeout\fR \fIn\fR .IP Set libvncserver rfbMaxClientWait to n seconds. On slow links that take a long time to paint the first screen libvncserver may hit the timeout and drop the connection. Default: 20 seconds. .PP \fB-nap,\fR \fB-nonap\fR .IP Monitor activity and if it is low take longer naps between screen polls to really cut down load when idle. Default: take naps .PP \fB-sb\fR \fItime\fR .IP Time in seconds after NO activity (e.g. screen blank) to really throttle down the screen polls (i.e. sleep for about 1.5 secs). Use 0 to disable. Default: 60 .PP \fB-nofbpm,\fR \fB-fbpm\fR .IP If the system supports the FBPM (Frame Buffer Power Management) extension (i.e. some Sun systems), then prevent the video h/w from going into a reduced power state when VNC clients are connected. .IP FBPM capable video h/w save energy when the workstation is idle by going into low power states (similar to DPMS for monitors). This interferes with x11vnc's polling of the framebuffer data. .IP "\fB-nofbpm\fR" means prevent FBPM low power states whenever VNC clients are connected, while "\fB-fbpm\fR" means to not monitor the FBPM state at all. See the .IR xset (1) manpage for details. \fB-nofbpm\fR is basically the same as running "xset fbpm force on" periodically. Default: \fB-fbpm\fR .PP \fB-noxdamage\fR .IP Do not use the X DAMAGE extension to detect framebuffer changes even if it is available. Use \fB-xdamage\fR if your default is to have it off. .IP x11vnc's use of the DAMAGE extension: 1) significantly reduces the load when the screen is not changing much, and 2) detects changed areas (small ones by default) more quickly. .IP Currently the DAMAGE extension is overly conservative and often reports large areas (e.g. a whole terminal or browser window) as damaged even though the actual changed region is much smaller (sometimes just a few pixels). So heuristics were introduced to skip large areas and use the damage rectangles only as "hints" for the traditional scanline polling. The following tuning parameters are introduced to adjust this behavior: .PP \fB-xd_area\fR \fIA\fR .IP Set the largest DAMAGE rectangle area \fIA\fR (in pixels: width * height) to trust as truly damaged: the rectangle will be copied from the framebuffer (slow) no matter what. Set to zero to trust *all* rectangles. Default: 20000 .PP \fB-xd_mem\fR \fIf\fR .IP Set how long DAMAGE rectangles should be "remembered", \fIf\fR is a floating point number and is in units of the scanline repeat cycle time (32 iterations). The default (1.0) should give no painting problems. Increase it if there are problems or decrease it to live on the edge (perhaps useful on a slow machine). .PP \fB-sigpipe\fR \fIstring\fR .IP Broken pipe (SIGPIPE) handling. \fIstring\fR can be "ignore" or "exit". For "ignore" libvncserver will handle the abrupt loss of a client and continue, for "exit" x11vnc will cleanup and exit at the 1st broken connection. Default: "ignore". This option is obsolete. .PP \fB-threads,\fR \fB-nothreads\fR .IP Whether or not to use the threaded libvncserver algorithm [rfbRunEventLoop] if libpthread is available Default: \fB-nothreads\fR .PP \fB-fs\fR \fIf\fR .IP If the fraction of changed tiles in a poll is greater than f, the whole screen is updated. Default: 0.75 .PP \fB-gaps\fR \fIn\fR .IP Heuristic to fill in gaps in rows or cols of n or less tiles. Used to improve text paging. Default: 4 .PP \fB-grow\fR \fIn\fR .IP Heuristic to grow islands of changed tiles n or wider by checking the tile near the boundary. Default: 3 .PP \fB-fuzz\fR \fIn\fR .IP Tolerance in pixels to mark a tiles edges as changed. Default: 2 .PP \fB-debug_tiles\fR .IP Print debugging output for tiles, fb updates, etc. .PP \fB-snapfb\fR .IP Instead of polling the X display framebuffer (fb) for changes, periodically copy all of X display fb into main memory and examine that copy for changes. Under some circumstances this will improve interactive response, or at least make things look smoother, but in others (most!) it will make the response worse. If the video h/w fb is such that reading small tiles is very slow this mode could help. To keep the "framerate" up the screen size x bpp cannot be too large. Note that this mode is very wasteful of memory I/O resources (it makes full screen copies even if nothing changes). It may be of use in video capture-like applications, or where window tearing is a problem. .PP \fB-rawfb\fR \fIstring\fR .IP Experimental option, instead of polling X, poll the memory object specified in \fIstring\fR. For shared memory segments it is of the form: "shm:N@WxHxB" which specifies a shmid N and framebuffer Width, Height, and Bits per pixel. To memory map .IR mmap (2) a file use: "map:/path/to/a/file@WxHxB". If there is trouble with mmap, use "file:/..." for slower .IR lseek (2) based reading. If you do not supply a type "map" is assumed if the file exists. .IP If string is "setup:cmd", then the command "cmd" is run and the first line from it is read and used as \fIstring\fR. This allows initializing the device, determining WxHxB, etc. These are often done as root so take care. .IP Optional suffixes are ":R/G/B" and "+O" to specify red, green, and blue masks and an offset into the memory object. If the masks are not provided x11vnc guesses them based on the bpp. .IP Examples: .IP \fB-rawfb\fR shm:210337933@800x600x32:ff/ff00/ff0000 .IP \fB-rawfb\fR map:/dev/fb0@1024x768x32 .IP \fB-rawfb\fR map:/tmp/Xvfb_screen0@640x480x8+3232 .IP \fB-rawfb\fR file:/tmp/my.pnm@250x200x24+37 .IP (see .IR ipcs (1) and .IR fbset (1) for the first two examples) .IP All user input is discarded by default (but see the \fB-pipeinput\fR option). Most of the X11 (screen, keyboard, mouse) options do not make sense and many will cause this mode to crash, so please think twice before setting/changing them. .IP If you don't want x11vnc to close the X DISPLAY in rawfb mode, then capitalize the prefix, SHM:, MAP:, FILE: Keeping the display open enables the default remote-control channel, which could be useful. Also, if you also specify \fB-noviewonly,\fR then the mouse and keyboard input are STILL sent to the X display, this usage should be very rare, i.e. doing something strange with /dev/fb0. .PP \fB-pipeinput\fR \fIcmd\fR .IP Another experimental option: it lets you supply an external command in \fIcmd\fR that x11vnc will pipe all of the user input events to in a simple format. In \fB-pipeinput\fR mode by default x11vnc will not process any of the user input events. If you prefix \fIcmd\fR with "tee:" it will both send them to the pipe command and process them. For a description of the format run "\fB-pipeinput\fR \fItee:/bin/cat\fR". Another prefix is "reopen" which means to reopen pipe if it exits. Separate multiple prefixes with commas. .IP In combination with \fB-rawfb\fR one might be able to do amusing things (e.g. control non-X devices). To facilitate this, if \fB-rawfb\fR is in effect then the value is stored in X11VNC_RAWFB_STR for the pipe command to use if it wants. Do 'env | grep X11VNC' for more. .PP \fB-gui\fR \fI[gui-opts]\fR .IP Start up a simple tcl/tk gui based on the the remote control options \fB-remote/-query\fR described below. Requires the "wish" program to be installed on the machine. "gui-opts" is not required: the default is to start up both the full gui and x11vnc with the gui showing up on the X display in the environment variable DISPLAY. .IP "gui-opts" can be a comma separated list of items. Currently there are these types of items: 1) a gui mode, a 2) gui "simplicity", 3) the X display the gui should display on, 4) a "tray" or "icon" mode, and 5) a gui geometry. .IP 1) The gui mode can be "start", "conn", or "wait" "start" is the default mode above and is not required. "conn" means do not automatically start up x11vnc, but instead just try to connect to an existing x11vnc process. "wait" means just start the gui and nothing else (you will later instruct the gui to start x11vnc or connect to an existing one.) .IP 2) The gui simplicity is off by default (a power-user gui with all options is presented) To start with something less daunting supply the string "simple" ("ez" is an alias for this). Once the gui is started you can toggle between the two with "Misc -> simple_gui". .IP 3) Note the possible confusion regarding the potentially two different X displays: x11vnc polls one, but you may want the gui to appear on another. For example, if you ssh in and x11vnc is not running yet you may want the gui to come back to you via your ssh redirected X display (e.g. localhost:10). .IP If you do not specify a gui X display in "gui-opts" then the DISPLAY environment variable and \fB-display\fR option are tried (in that order). Regarding the x11vnc X display the gui will try to communication with, it first tries \fB-display\fR and then DISPLAY. For example, "x11vnc \fB-display\fR :0 \fB-gui\fR otherhost:0", will remote control an x11vnc polling :0 and display the gui on otherhost:0 The "tray/icon" mode below reverses this preference, preferring to display on the x11vnc display. .IP 4) When "tray" or "icon" is specified, the gui presents itself as a small icon with behavior typical of a "system tray" or "dock applet". The color of the icon indicates status (connected clients) and there is also a balloon status. Clicking on the icon gives a menu from which properties, etc, can be set and the full gui is available under "Advanced". To be fully functional, the gui mode should be "start" (the default). .IP For "icon" the gui just a small standalone window. For "tray" it will attempt to embed itself in the "system tray" if possible. If "=setpass" is appended then at startup the X11 user will be prompted to set the VNC session password. If = is appended that icon will attempt to embed itself in the window given by hexnumber. Use =noadvanced to disable the full gui. (To supply more than one, use "+" sign). E.g. \fB-gui\fR tray=setpass and \fB-gui\fR icon=0x3600028 .IP Other modes: "full", the default and need not be specified. "\fB-gui\fR \fInone\fR", do not show a gui, useful to override a ~/.x11vncrc setting, etc. .IP 5) When "geom=+X+Y" is specified, that geometry is passed to the gui toplevel. This is the icon in icon/tray mode, or the full gui otherwise. You can also specify width and height, i.e. WxH+X+Y, but it is not recommended. In "tray" mode the geometry is ignored unless the system tray manager does not seem to be running. One could imagine using something like "\fB-gui\fR \fItray,geom=+4000+4000\fR" with a display manager to keep the gui invisible until someone logs in... .IP More icon tricks, "icon=minimal" gives an icon just with the VNC display number. You can also set the font with "iconfont=...". The following could be useful: "\fB-gui\fR \fIicon=minimal,iconfont=5x8,geom=24x10+0-0\fR" .IP General examples of the \fB-gui\fR option: "x11vnc \fB-gui",\fR "x11vnc \fB-gui\fR ez" "x11vnc \fB-gui\fR localhost:10", "x11vnc \fB-gui\fR conn,host:0", "x11vnc \fB-gui\fR tray,ez" "x11vnc \fB-gui\fR tray=setpass" .IP If you do not intend to start x11vnc from the gui (i.e. just remote control an existing one), then the gui process can run on a different machine from the x11vnc server as long as X permissions, etc. permit communication between the two. .PP \fB-remote\fR \fIcommand\fR .IP Remotely control some aspects of an already running x11vnc server. "\fB-R\fR" and "\fB-r\fR" are aliases for "\fB-remote\fR". After the remote control command is sent to the running server the 'x11vnc \fB-remote\fR ...' command exits. You can often use the \fB-query\fR command (see below) to see if the x11vnc server processed your \fB-remote\fR command. .IP The default communication channel is that of X properties (specifically X11VNC_REMOTE), and so this command must be run with correct settings for DISPLAY and possibly XAUTHORITY to connect to the X server and set the property. Alternatively, use the \fB-display\fR and \fB-auth\fR options to set them to the correct values. The running server cannot use the \fB-novncconnect\fR option because that disables the communication channel. See below for alternate channels. .IP For example: 'x11vnc \fB-remote\fR stop' (which is the same as \'x11vnc \fB-R\fR stop') will close down the x11vnc server. \'x11vnc \fB-R\fR shared' will enable shared connections, and \'x11vnc \fB-R\fR scale:3/4' will rescale the desktop. .IP .IP The following \fB-remote/-R\fR commands are supported: .IP stop terminate the server, same as "quit" "exit" or "shutdown". .IP ping see if the x11vnc server responds. Return is: ans=ping: .IP blacken try to push a black fb update to all clients (due to timings a client could miss it). Same as "zero", also "zero:x1,y1,x2,y2" for a rectangle. .IP refresh send the entire fb to all clients. .IP reset recreate the fb, polling memory, etc. .IP id:windowid set \fB-id\fR window to "windowid". empty or "root" to go back to root window .IP sid:windowid set \fB-sid\fR window to "windowid" .IP waitmapped wait until subwin is mapped. .IP nowaitmapped do not wait until subwin is mapped. .IP clip:WxH+X+Y set \fB-clip\fR mode to "WxH+X+Y" .IP flashcmap enable \fB-flashcmap\fR mode. .IP noflashcmap disable \fB-flashcmap\fR mode. .IP shiftcmap:n set \fB-shiftcmap\fR to n. .IP notruecolor enable \fB-notruecolor\fR mode. .IP truecolor disable \fB-notruecolor\fR mode. .IP overlay enable \fB-overlay\fR mode (if applicable). .IP nooverlay disable \fB-overlay\fR mode. .IP overlay_cursor in \fB-overlay\fR mode, enable cursor drawing. .IP overlay_nocursor disable cursor drawing. same as nooverlay_cursor. .IP 8to24 enable \fB-8to24\fR mode (if applicable). .IP no8to24 disable \fB-8to24\fR mode. .IP 8to24_opts:str set the \fB-8to24\fR opts to "str". .IP visual:vis set \fB-visual\fR to "vis" .IP scale:frac set \fB-scale\fR to "frac" .IP scale_cursor:f set \fB-scale_cursor\fR to "f" .IP viewonly enable \fB-viewonly\fR mode. .IP noviewonly disable \fB-viewonly\fR mode. .IP shared enable \fB-shared\fR mode. .IP noshared disable \fB-shared\fR mode. .IP forever enable \fB-forever\fR mode. .IP noforever disable \fB-forever\fR mode. .IP timeout:n reset \fB-timeout\fR to n, if there are currently no clients, exit unless one connects in the next n secs. .IP filexfer enable filetransfer for new clients. .IP nofilexfer disable filetransfer for new clients. .IP http enable http client connections. .IP nohttp disable http client connections. .IP deny deny any new connections, same as "lock" .IP nodeny allow new connections, same as "unlock" .IP connect:host do reverse connection to host, "host" may be a comma separated list of hosts or host:ports. See \fB-connect.\fR Passwords required as with fwd connections. See X11VNC_REVERSE_CONNECTION_NO_AUTH=1 .IP disconnect:host disconnect any clients from "host" same as "close:host". Use host "all" to close all current clients. If you know the client internal hex ID, e.g. 0x3 (returned by "\fB-query\fR \fIclients\fR" and RFB_CLIENT_ID) you can use that too. .IP allowonce:host For the next connection only, allow connection from "host". .IP allow:hostlist set \fB-allow\fR list to (comma separated) "hostlist". See \fB-allow\fR and \fB-localhost.\fR Do not use with \fB-allow\fR /path/to/file Use "+host" to add a single host, and use "\fB-host\fR" to delete a single host .IP localhost enable \fB-localhost\fR mode .IP nolocalhost disable \fB-localhost\fR mode .IP listen:str set \fB-listen\fR to str, empty to disable. .IP nolookup enable \fB-nolookup\fR mode. .IP lookup disable \fB-nolookup\fR mode. .IP input:str set \fB-input\fR to "str", empty to disable. .IP client_input:str set the K, M, B \fB-input\fR on a per-client basis. select which client as for disconnect, e.g. client_input:host:MB or client_input:0x2:K .IP accept:cmd set \fB-accept\fR "cmd" (empty to disable). .IP afteraccept:cmd set \fB-afteraccept\fR (empty to disable). .IP gone:cmd set \fB-gone\fR "cmd" (empty to disable). .IP noshm enable \fB-noshm\fR mode. .IP shm disable \fB-noshm\fR mode (i.e. use shm). .IP flipbyteorder enable \fB-flipbyteorder\fR mode, you may need to set noshm for this to do something. .IP noflipbyteorder disable \fB-flipbyteorder\fR mode. .IP onetile enable \fB-onetile\fR mode. (you may need to set shm for this to do something) .IP noonetile disable \fB-onetile\fR mode. .IP solid enable \fB-solid\fR mode .IP nosolid disable \fB-solid\fR mode. .IP solid_color:color set \fB-solid\fR color (and apply it). .IP blackout:str set \fB-blackout\fR "str" (empty to disable). See \fB-blackout\fR for the form of "str" (basically: WxH+X+Y,...) Use "+WxH+X+Y" to append a single rectangle use "-WxH+X+Y" to delete one .IP xinerama enable \fB-xinerama\fR mode. (if applicable) .IP noxinerama disable \fB-xinerama\fR mode. .IP xtrap enable \fB-xtrap\fR input mode(if applicable) .IP noxtrap disable \fB-xtrap\fR input mode. .IP xrandr enable \fB-xrandr\fR mode. (if applicable) .IP noxrandr disable \fB-xrandr\fR mode. .IP xrandr_mode:mode set the \fB-xrandr\fR mode to "mode". .IP padgeom:WxH set \fB-padgeom\fR to WxH (empty to disable) If WxH is "force" or "do" the padded geometry fb is immediately applied. .IP quiet enable \fB-quiet\fR mode. .IP noquiet disable \fB-quiet\fR mode. .IP modtweak enable \fB-modtweak\fR mode. .IP nomodtweak enable \fB-nomodtweak\fR mode. .IP xkb enable \fB-xkb\fR modtweak mode. .IP noxkb disable \fB-xkb\fR modtweak mode. .IP skip_keycodes:str enable \fB-xkb\fR \fB-skip_keycodes\fR "str". .IP sloppy_keys enable \fB-sloppy_keys\fR mode. .IP nosloppy_keys disable \fB-sloppy_keys\fR mode. .IP skip_dups enable \fB-skip_dups\fR mode. .IP noskip_dups disable \fB-skip_dups\fR mode. .IP add_keysyms enable \fB-add_keysyms\fR mode. .IP noadd_keysyms stop adding keysyms. those added will still be removed at exit. .IP clear_mods enable \fB-clear_mods\fR mode and clear them. .IP noclear_mods disable \fB-clear_mods\fR mode. .IP clear_keys enable \fB-clear_keys\fR mode and clear them. .IP noclear_keys disable \fB-clear_keys\fR mode. .IP remap:str set \fB-remap\fR "str" (empty to disable). See \fB-remap\fR for the form of "str" (basically: key1-key2,key3-key4,...) Use "+key1-key2" to append a single keymapping, use "-key1-key2" to delete. .IP norepeat enable \fB-norepeat\fR mode. .IP repeat disable \fB-norepeat\fR mode. .IP nofb enable \fB-nofb\fR mode. .IP fb disable \fB-nofb\fR mode. .IP bell enable bell (if supported). .IP nobell disable bell. .IP nosel enable \fB-nosel\fR mode. .IP sel disable \fB-nosel\fR mode. .IP noprimary enable \fB-noprimary\fR mode. .IP primary disable \fB-noprimary\fR mode. .IP nosetprimary enable \fB-nosetprimary\fR mode. .IP setprimary disable \fB-nosetprimary\fR mode. .IP noclipboard enable \fB-noclipboard\fR mode. .IP clipboard disable \fB-noclipboard\fR mode. .IP nosetclipboard enable \fB-nosetclipboard\fR mode. .IP setclipboard disable \fB-nosetclipboard\fR mode. .IP seldir:str set \fB-seldir\fR to "str" .IP cursor:mode enable \fB-cursor\fR "mode". .IP show_cursor enable showing a cursor. .IP noshow_cursor disable showing a cursor. (same as "nocursor") .IP arrow:n set \fB-arrow\fR to alternate n. .IP xfixes enable xfixes cursor shape mode. .IP noxfixes disable xfixes cursor shape mode. .IP alphacut:n set \fB-alphacut\fR to n. .IP alphafrac:f set \fB-alphafrac\fR to f. .IP alpharemove enable \fB-alpharemove\fR mode. .IP noalpharemove disable \fB-alpharemove\fR mode. .IP alphablend disable \fB-noalphablend\fR mode. .IP noalphablend enable \fB-noalphablend\fR mode. .IP cursorshape disable \fB-nocursorshape\fR mode. .IP nocursorshape enable \fB-nocursorshape\fR mode. .IP cursorpos disable \fB-nocursorpos\fR mode. .IP nocursorpos enable \fB-nocursorpos\fR mode. .IP xwarp enable \fB-xwarppointer\fR mode. .IP noxwarp disable \fB-xwarppointer\fR mode. .IP buttonmap:str set \fB-buttonmap\fR "str", empty to disable .IP dragging disable \fB-nodragging\fR mode. .IP nodragging enable \fB-nodragging\fR mode. .IP wireframe enable \fB-wireframe\fR mode. same as "wf" .IP nowireframe disable \fB-wireframe\fR mode. same as "nowf" .IP wireframe:str enable \fB-wireframe\fR mode string. .IP wireframe_mode:str enable \fB-wireframe\fR mode string. .IP wirecopyrect:str set \fB-wirecopyrect\fR string. same as "wcr:" .IP scrollcopyrect:str set \fB-scrollcopyrect\fR string. same "scr" .IP noscrollcopyrect disable \fB-scrollcopyrect__mode_.\fR "noscr" .IP scr_area:n set \fB-scr_area\fR to n .IP scr_skip:list set \fB-scr_skip\fR to "list" .IP scr_inc:list set \fB-scr_inc\fR to "list" .IP scr_keys:list set \fB-scr_keys\fR to "list" .IP scr_term:list set \fB-scr_term\fR to "list" .IP scr_keyrepeat:str set \fB-scr_keyrepeat\fR to "str" .IP scr_parms:str set \fB-scr_parms\fR parameters. .IP fixscreen:str set \fB-fixscreen\fR to "str". .IP noxrecord disable all use of RECORD extension. .IP xrecord enable use of RECORD extension. .IP reset_record reset RECORD extension (if avail.) .IP pointer_mode:n set \fB-pointer_mode\fR to n. same as "pm" .IP input_skip:n set \fB-input_skip\fR to n. .IP speeds:str set \fB-speeds\fR to str. .IP wmdt:str set \fB-wmdt\fR to str. .IP debug_pointer enable \fB-debug_pointer,\fR same as "dp" .IP nodebug_pointer disable \fB-debug_pointer,\fR same as "nodp" .IP debug_keyboard enable \fB-debug_keyboard,\fR same as "dk" .IP nodebug_keyboard disable \fB-debug_keyboard,\fR same as "nodk" .IP defer:n set \fB-defer\fR to n ms,same as deferupdate:n .IP wait:n set \fB-wait\fR to n ms. .IP wait_ui:f set \fB-wait_ui\fR factor to f. .IP wait_bog disable \fB-nowait_bog\fR mode. .IP nowait_bog enable \fB-nowait_bog\fR mode. .IP slow_fb:f set \fB-slow_fb\fR to f seconds. .IP readtimeout:n set read timeout to n seconds. .IP nap enable \fB-nap\fR mode. .IP nonap disable \fB-nap\fR mode. .IP sb:n set \fB-sb\fR to n s, same as screen_blank:n .IP fbpm disable \fB-nofbpm\fR mode. .IP nofbpm enable \fB-nofbpm\fR mode. .IP xdamage enable xdamage polling hints. .IP noxdamage disable xdamage polling hints. .IP xd_area:A set \fB-xd_area\fR max pixel area to "A" .IP xd_mem:f set \fB-xd_mem\fR remembrance to "f" .IP fs:frac set \fB-fs\fR fraction to "frac", e.g. 0.5 .IP gaps:n set \fB-gaps\fR to n. .IP grow:n set \fB-grow\fR to n. .IP fuzz:n set \fB-fuzz\fR to n. .IP snapfb enable \fB-snapfb\fR mode. .IP nosnapfb disable \fB-snapfb\fR mode. .IP rawfb:str set \fB-rawfb\fR mode to "str". .IP progressive:n set libvncserver \fB-progressive\fR slice height parameter to n. .IP desktop:str set \fB-desktop\fR name to str for new clients. .IP rfbport:n set \fB-rfbport\fR to n. .IP httpport:n set \fB-httpport\fR to n. .IP httpdir:dir set \fB-httpdir\fR to dir (and enable http). .IP enablehttpproxy enable \fB-enablehttpproxy\fR mode. .IP noenablehttpproxy disable \fB-enablehttpproxy\fR mode. .IP alwaysshared enable \fB-alwaysshared\fR mode. .IP noalwaysshared disable \fB-alwaysshared\fR mode. (may interfere with other options) .IP nevershared enable \fB-nevershared\fR mode. .IP nonevershared disable \fB-nevershared\fR mode. (may interfere with other options) .IP dontdisconnect enable \fB-dontdisconnect\fR mode. .IP nodontdisconnect disable \fB-dontdisconnect\fR mode. (may interfere with other options) .IP debug_xevents enable debugging X events. .IP nodebug_xevents disable debugging X events. .IP debug_xdamage enable debugging X DAMAGE mechanism. .IP nodebug_xdamage disable debugging X DAMAGE mechanism. .IP debug_wireframe enable debugging wireframe mechanism. .IP nodebug_wireframe disable debugging wireframe mechanism. .IP debug_scroll enable debugging scrollcopy mechanism. .IP nodebug_scroll disable debugging scrollcopy mechanism. .IP debug_tiles enable \fB-debug_tiles\fR .IP nodebug_tiles disable \fB-debug_tiles\fR .IP debug_grabs enable \fB-debug_grabs\fR .IP nodebug_grabs disable \fB-debug_grabs\fR .IP debug_sel enable \fB-debug_sel\fR .IP nodebug_sel disable \fB-debug_sel\fR .IP dbg enable \fB-dbg\fR crash shell .IP nodbg disable \fB-dbg\fR crash shell .IP .IP noremote disable the \fB-remote\fR command processing, it cannot be turned back on. .IP .IP The .IR vncconnect (1) command from standard VNC .IP distributions may also be used if string is prefixed .IP with "cmd=" E.g. 'vncconnect cmd=stop'. Under some .IP circumstances .IR xprop (1) can used if it supports \fB-set\fR .IP (see the FAQ). .IP .IP If "\fB-connect\fR \fI/path/to/file\fR" has been supplied to the .IP running x11vnc server then that file can be used as a .IP communication channel (this is the only way to remote .IP control one of many x11vnc's polling the same X display) .IP Simply run: 'x11vnc \fB-connect\fR /path/to/file \fB-remote\fR ...' .IP or you can directly write to the file via something .IP like: "echo cmd=stop > /path/to/file", etc. .PP \fB-query\fR \fIvariable\fR .IP Like \fB-remote,\fR except just query the value of \fIvariable\fR. "\fB-Q\fR" is an alias for "\fB-query\fR". Multiple queries can be done by separating variables by commas, e.g. \fB-query\fR var1,var2. The results come back in the form ans=var1:value1,ans=var2:value2,... to the standard output. If a variable is read-only, it comes back with prefix "aro=" instead of "ans=". .IP Some \fB-remote\fR commands are pure actions that do not make sense as variables, e.g. "stop" or "disconnect", in these cases the value returned is "N/A". To direct a query straight to the X11VNC_REMOTE property or connect file use "qry=..." instead of "cmd=..." .IP Here is the current list of "variables" that can be supplied to the \fB-query\fR command. This includes the "N/A" ones that return no useful info. For variables names that do not correspond to an x11vnc option or remote command, we hope the name makes it obvious what the returned value corresponds to (hint: the ext_* variables correspond to the presence of X extensions): .IP ans= stop quit exit shutdown ping blacken zero refresh reset close disconnect id sid waitmapped nowaitmapped clip flashcmap noflashcmap shiftcmap truecolor notruecolor overlay nooverlay overlay_cursor overlay_yescursor nooverlay_nocursor nooverlay_cursor nooverlay_yescursor overlay_nocursor 8to24 no8to24 8to24_opts visual scale scale_cursor viewonly noviewonly shared noshared forever noforever once timeout filexfer nofilexfer deny lock nodeny unlock connect allowonce allow localhost nolocalhost listen lookup nolookup accept afteraccept gone shm noshm flipbyteorder noflipbyteorder onetile noonetile solid_color solid nosolid blackout xinerama noxinerama xtrap noxtrap xrandr noxrandr xrandr_mode padgeom quiet q noquiet modtweak nomodtweak xkb noxkb skip_keycodes sloppy_keys nosloppy_keys skip_dups noskip_dups add_keysyms noadd_keysyms clear_mods noclear_mods clear_keys noclear_keys remap repeat norepeat fb nofb bell nobell sel nosel primary noprimary setprimary nosetprimary clipboard noclipboard setclipboard nosetclipboard seldir cursorshape nocursorshape cursorpos nocursorpos cursor show_cursor noshow_cursor nocursor arrow xfixes noxfixes xdamage noxdamage xd_area xd_mem alphacut alphafrac alpharemove noalpharemove alphablend noalphablend xwarppointer xwarp noxwarppointer noxwarp buttonmap dragging nodragging wireframe_mode wireframe wf nowireframe nowf wirecopyrect wcr nowirecopyrect nowcr scr_area scr_skip scr_inc scr_keys scr_term scr_keyrepeat scr_parms scrollcopyrect scr noscrollcopyrect noscr fixscreen noxrecord xrecord reset_record pointer_mode pm input_skip input client_input speeds wmdt debug_pointer dp nodebug_pointer nodp debug_keyboard dk nodebug_keyboard nodk deferupdate defer wait_ui wait_bog nowait_bog slow_fb wait readtimeout nap nonap sb screen_blank fbpm nofbpm fs gaps grow fuzz snapfb nosnapfb rawfb progressive rfbport http nohttp httpport httpdir enablehttpproxy noenablehttpproxy alwaysshared noalwaysshared nevershared noalwaysshared dontdisconnect nodontdisconnect desktop debug_xevents nodebug_xevents debug_xevents debug_xdamage nodebug_xdamage debug_xdamage debug_wireframe nodebug_wireframe debug_wireframe debug_scroll nodebug_scroll debug_scroll debug_tiles dbt nodebug_tiles nodbt debug_tiles debug_grabs nodebug_grabs debug_sel nodebug_sel dbg nodbg noremote .IP aro= noop display vncdisplay desktopname guess_desktop http_url auth xauth users rootshift clipshift scale_str scaled_x scaled_y scale_numer scale_denom scale_fac scaling_blend scaling_nomult4 scaling_pad scaling_interpolate inetd privremote unsafe safer nocmds passwdfile unixpw unixpw_nis unixpw_list ssl ssl_pem sslverify stunnel stunnel_pem https usepw using_shm logfile o flag rc norc h help V version lastmod bg sigpipe threads readrate netrate netlatency pipeinput clients client_count pid ext_xtest ext_xtrap ext_xrecord ext_xkb ext_xshm ext_xinerama ext_overlay ext_xfixes ext_xdamage ext_xrandr rootwin num_buttons button_mask mouse_x mouse_y bpp depth indexed_color dpy_x dpy_y wdpy_x wdpy_y off_x off_y cdpy_x cdpy_y coff_x coff_y rfbauth passwd viewpasswd .PP \fB-QD\fR \fIvariable\fR .IP Just like \fB-query\fR variable, but returns the default value for that parameter (no running x11vnc server is consulted) .PP \fB-sync\fR .IP By default \fB-remote\fR commands are run asynchronously, that is, the request is posted and the program immediately exits. Use \fB-sync\fR to have the program wait for an acknowledgement from the x11vnc server that command was processed (somehow). On the other hand \fB-query\fR requests are always processed synchronously because they have to wait for the answer. .IP Also note that if both \fB-remote\fR and \fB-query\fR requests are supplied on the command line, the \fB-remote\fR is processed first (synchronously: no need for \fB-sync),\fR and then the \fB-query\fR request is processed in the normal way. This allows for a reliable way to see if the \fB-remote\fR command was processed by querying for any new settings. Note however that there is timeout of a few seconds so if the x11vnc takes longer than that to process the requests the requestor will think that a failure has taken place. .PP \fB-noremote,\fR \fB-yesremote\fR .IP Do not process any remote control commands or queries. Do process remote control commands or queries. Default: \fB-yesremote\fR .IP A note about security wrt remote control commands. If someone can connect to the X display and change the property X11VNC_REMOTE, then they can remotely control x11vnc. Normally access to the X display is protected. Note that if they can modify X11VNC_REMOTE on the X server, they have enough permissions to also run their own x11vnc and thus have complete control of the desktop. If the "\fB-connect\fR \fI/path/to/file\fR" channel is being used, obviously anyone who can write to /path/to/file can remotely control x11vnc. So be sure to protect the X display and that file's write permissions. See \fB-privremote\fR below. .IP If you are paranoid and do not think \fB-noremote\fR is enough, to disable the X11VNC_REMOTE property channel completely use \fB-novncconnect,\fR or use the \fB-safer\fR option that shuts many things off. .PP \fB-unsafe\fR .IP A few remote commands are disabled by default (currently: id:pick, accept:, gone:, and rawfb:setup:) because they are associated with running external programs. If you specify \fB-unsafe,\fR then these remote-control commands are allowed. Note that you can still specify these parameters on the command line, they just cannot be invoked via remote-control. .PP \fB-safer\fR .IP Equivalent to: \fB-novncconnect\fR \fB-noremote\fR and prohibiting \fB-gui\fR and the \fB-connect\fR file. Shuts off communcation channels. .PP \fB-privremote\fR .IP Perform some sanity checks and disable remote-control commands if it appears that the X DISPLAY and/or connectfile can be accessed by other users. Once remote-control is disabled it cannot be turned back on. .PP \fB-nocmds\fR .IP No external commands (e.g. .IR system (3) , .IR popen (3) , .IR exec (3) ) will be run. .PP \fB-deny_all\fR .IP For use with \fB-remote\fR nodeny: start out denying all incoming clients until "\fB-remote\fR \fInodeny\fR" is used to let them in. .PP These options are passed to libvncserver: .PP \fB-rfbport\fR \fIport\fR .IP TCP port for RFB protocol .PP \fB-rfbwait\fR \fItime\fR .IP max time in ms to wait for RFB client .PP \fB-rfbauth\fR \fIpasswd-file\fR .IP use authentication on RFB protocol (use 'storepasswd' to create a password file) .PP \fB-passwd\fR \fIplain-password\fR .IP use authentication (use plain-password as password, USE AT YOUR RISK) .PP \fB-deferupdate\fR \fItime\fR .IP time in ms to defer updates (default 40) .PP \fB-deferptrupdate\fR \fItime\fR .IP time in ms to defer pointer updates (default none) .PP \fB-desktop\fR \fIname\fR .IP VNC desktop name (default "LibVNCServer") .PP \fB-alwaysshared\fR .IP always treat new clients as shared .PP \fB-nevershared\fR .IP never treat new clients as shared .PP \fB-dontdisconnect\fR .IP don't disconnect existing clients when a new non-shared connection comes in (refuse new connection instead) .PP \fB-httpdir\fR \fIdir-path\fR .IP enable http server using dir-path home .PP \fB-httpport\fR \fIportnum\fR .IP use portnum for http connection .PP \fB-enablehttpproxy\fR .IP enable http proxy support .PP \fB-progressive\fR \fIheight\fR .IP enable progressive updating for slow links .PP \fB-listen\fR \fIipaddr\fR .IP listen for connections only on network interface with addr ipaddr. '-listen localhost' and hostname work too. .PP libvncserver-tight-extension options: .PP \fB-disablefiletransfer\fR .IP disable file transfer .PP \fB-ftproot\fR \fIstring\fR .IP set ftp root .SH "FILES" .IR $HOME/.x11vncrc , .IR $HOME/.Xauthority .SH "ENVIRONMENT" .IR DISPLAY , .IR XAUTHORITY , .IR HOME .PP The following are set for the auxiliary commands run by \fB-accept\fR and \fB-gone\fR: .PP .IR RFB_CLIENT_IP , .IR RFB_CLIENT_PORT , .IR RFB_SERVER_IP , .IR RFB_SERVER_PORT , .IR RFB_X11VNC_PID , .IR RFB_CLIENT_ID , .IR RFB_CLIENT_COUNT , .IR RFB_MODE .SH "SEE ALSO" .IR vncviewer (1), .IR vncpasswd (1), .IR vncconnect (1), .IR vncserver (1), .IR Xvnc (1), .IR xev (1), .IR xdpyinfo (1), .IR xwininfo (1), .IR xprop (1), .IR xmodmap (1), .IR xrandr (1), .IR Xserver (1), .IR xauth (1), .IR xhost (1), .IR Xsecurity (7), .IR xmessage (1), .IR XGetImage (3X11), .IR ipcrm (1), .IR inetd (1), .IR xdm (1), .IR gdm (1), .IR kdm (1), .IR ssh (1), .IR stunnel (8), .IR su (1), .IR http://www.tightvnc.com , .IR http://www.realvnc.com , .IR http://www.karlrunge.com/x11vnc/ , .IR http://www.karlrunge.com/x11vnc/#faq .SH AUTHORS x11vnc was written by Karl J. Runge , it is part of the LibVNCServer project . This manual page is based one the one written by Ludovic Drolez , for the Debian project (both may be used by others).