Provided by: xpra_2.4.3+dfsg1-1_amd64 bug

NAME

       xpra - viewer for remote, persistent X applications

SYNOPSIS

       xpra start [:DISPLAY] | xpra start ssh:HOST:DISPLAY | xpra start-desktop [:DISPLAY] | xpra
            start-desktop ssh:HOST:DISPLAY [OPTIONS..]
       xpra attach [CONNECTIONSTRING] [OPTIONS..]
       xpra shadow [:DISPLAY] | ssh:[USER@]HOST[:DISPLAY] [OPTIONS..]
       xpra proxy [:DISPLAY] [OPTIONS..]
       xpra stop | xpra exit | xpra detach | xpra screenshot filename | xpra version | xpra  info
            [CONNECTIONSTRING] [OPTIONS..]
       xpra  control  [CONNECTIONSTRING]  command  [arguments..]  [--ssh=CMD] [--remote-xpra=CMD]
            [--socket-dir=DIR] [--socket-dirs=DIRS]
       xpra initenv [--socket-dir=DIR]
       xpra list [--socket-dir=DIR]
       xpra showconfig [OPTIONS..]
       xpra list-mdns
       xpra upgrade :[DISPLAY] [...any options accepted by xpra start...]

DESCRIPTION

       Xpra is a tool which allows you to run X programs — usually on a remote host  —  and  then
       direct  their display to your local machine, disconnect from these programs, and reconnect
       from the same or another machine, all without losing any state.  It differs from  standard
       X  forwarding  in  that  it  allows  disconnection and reconnection without disrupting the
       forwarded application; it differs from VNC and similar remote display technologies in that
       xpra  can  run  rootless:  i.e.,  applications forwarded by xpra appear on your desktop as
       normal windows managed by your window manager, rather than being all  "trapped  in  a  box
       together".   Xpra  also uses a custom protocol that is self-tuning and relatively latency-
       insensitive, and thus is usable over network connections that are too slow  or  unreliable
       for standard X forwarding.  Xpra can also be used to shadow an existing X11 display, or in
       desktop mode where it behaves more like VNC.

       By default the Xpra server announces available sessions (username and display number)  via
       mDNS to the local network. Use mdns=no to disable it.

CONNECTION STRINGS

       Xpra  supports  many  types  of  connection strings (some may require extra packages to be
       installed):

   :DISPLAY
       Local displays: this is the simplest form and is only valid for the current local displays
       of the current user.

   tcp://[USERNAME@]HOST:PORT[/DISPLAY]
       TCP  mode  uses  port  numbers and not display numbers. If multiple displays are available
       through a single TCP port (ie: using a proxy  server),  then  one  can  also  specify  the
       display number.

   ssl://[USERNAME@]HOST:PORT[/DISPLAY]
       SSL adds a secure socket layer on top of the TCP mode.

   vsock://[USERNAME[:PASSWORD]@]HOST:PORT
       Almost identical to the TCP mode, but using AF_VSOCK for transport.

   ws://[USERNAME[:PASSWORD]@]HOST:PORT/[DISPLAY]
       Connect using websocket protocol.

   wss://[USERNAME[:PASSWORD]@]HOST:PORT/[DISPLAY]
       Connect using secure websocket protocol. (websocket with SSL)

   ssh://[USERNAME[:PASSWORD]@]HOST[:SSH_PORT]/DISPLAY
       Further options can be specified using the --ssh command line option.

       For     backwards     compatibility,     SSH    mode    also    supports    the    syntax:
       ssh:[USERNAME[:PASSWORD]@HOST:DISPLAY but this form does not support  specifying  the  SSH
       port  number.   Older  versions  also  used  the  form  protocol:host:port,  but users are
       encouraged to move to a more standard URI format using :// as separator.

       The password need only be specified when the server  authentication  module  requires  it.
       (ie:  often  when  authenticating against MS Windows servers, or with multifile and sqlite
       authentication modules)

EXAMPLES

       xpra start :7
            Start an xpra server using display number :7.  Note: using DISPLAY=:7 xterm to  start
            applications  against  a  specific  display  is  not recommended. Always prefer using
            xpra's --start= command line option instead.  See this next example:

       xpra start --start=firefox
            Start an xpra server, choosing a display automatically  and  start  firefox  on  that
            virtual display.  No window will appear until you attach with xpra attach.  The start
            child commands will inherit an environment tailored for running under xpra.

       xpra start ssh:bigbox:7 --start=xterm
            Start an xpra server on bigbox with an xterm in it, and connect to it.

       xpra start-desktop --start=xfce4-session
            Start an xfce session in a nested X11 server on  an  automatically  assigned  display
            number.

       xpra list
            Show a list of xpra servers you have running on the current host.

       xpra list-mdns
            Show a list of xpra servers found via mDNS. (local network)

       xpra showconfig
            Shows  the  configuration  that  would  be  used with other sub-commands, taking into
            account the command line arguments.

       xpra attach :7
            Attach to the xpra server that is using local display number :7.  Any apps running on
            that server will appear on your screen.

       xpra attach ssh:foo@frodo:7
            Use ssh to attach to the xpra server that is running on machine frodo as user foo and
            using display :7.  Any apps running on that server will appear on your local screen.

       xpra start :7 --start=screen
            Start an xpra server and a screen(1) session.  If  any  of  the  applications  inside
            screen attempt to use X, they will be directed to the xpra server.

DISPLAYS

       Understanding the basic idea of displays is critical to using xpra successfully.

       The  idea comes from standard X.  If you have multiple X servers running on the same host,
       then there has to be some way to distinguish them.  X does this by assigning each server a
       small, unique integer called (perhaps confusingly) its "display".  In the common case of a
       desktop machine that has only one X server running, that  server  uses  display  ":0"  (or
       sometimes  you'll  see ":0.0", which is effectively the same).  When an application starts
       under X, it needs to know how to find the right X server to use; it does this by  checking
       the environment variable $DISPLAY.

       Xpra  faces  a  similar  problem  — there may be multiple xpra servers running on the same
       host, as well as multiple X servers.  It solves this problem by re-using  X's  solution  —
       each  xpra  server  has a display associated with it.  This display functions as both an X
       display (for when xpra is talking to X applications) and as an identifier  by  which  xpra
       clients (like xpra attach) can locate the xpra server.

       You  may  omit  the display number when using xpra start: a display will be chosen for you
       automatically.  The display number chosen will be shown in the log output, you should also
       be  able  to  see it with xpra list.  On Microsoft Windows and Mac OSX, the display number
       should be omitted.

       Otherwise, when starting an xpra server, you may want to specify the name of  the  display
       to  use.   To  do  this, simply pick any number you like and stick a colon in front of it.
       For instance :7, :12, and :3117 are all valid display names.  Just keep in mind that:

       ·      Every X or xpra server that is running on a single machine  must  use  a  different
              display name.  If you pick a number that is already in use then xpra will not work.

       ·      The first few numbers (0, 1, 2) are commonly used by real X servers.

       ·      Everyone  who  connects  to  a given machine using ssh(1) with X forwarding enabled
              will also use a display number; ssh generally picks numbers near ten (10,  11,  12,
              ...).

       When  specifying  an  xpra  server to a client program like xpra attach, xpra detach, xpra
       stop, xpra exit, xpra version, xpra info, xpra list or xpra screenshot then you can use  a
       display  of  the  form :DISPLAY to refer to a server on the local host, or one of the form
       ssh:[USER@]HOST:DISPLAY to refer to a server on a remote  host;  xpra  will  automatically
       connect  to  the  remote  host using ssh(1).  Generally, if you have only one xpra session
       running on a machine (which you can verify by running xpra list on that machine), then you
       can omit the number entirely; xpra attach alone will attach to the lone xpra server on the
       current machine regardless of its number, xpra attach ssh:frodo will similarly  attach  to
       the lone xpra session on a remote machine.

       Connecting  using  the  display  number  assumes  that  the client and server use the same
       configuration for socket directories, or at least that the client can find at least one of
       the directories used by the unix domain sockets (see bind, socket-dir and socket-dirs).

       If the xpra server was given the --bind-tcp, --bind-ssl --bind-udp=[HOST]:PORT, --bind-ws,
       --bind-wss or --bind-vsock option when started then you can also connect  to  it  using  a
       display  of  the  form  tcp://HOST:PORT, udp://HOST:PORT, ssl://HOST:PORT, ws://HOST:PORT,
       wss://HOST:PORT or vsock://HOST:PORT.  (Notice that ssh: takes an optional display number,
       while those take a required port number.)

SUBCOMMANDS

   xpra start
       This  command  starts  a new xpra server, including any necessary setup.  (When starting a
       remote server with the ssh:HOST:DISPLAY syntax, the new session will also be attached.)

   xpra start-desktop
       Starts a nested X11 server, all child commands will be started in the nested X11 server.

   xpra attach
       This command attaches to a running xpra server, and forwards any applications  using  that
       server to appear on your current screen.

   xpra detach
       Detaches the given xpra display.

   xpra screenshot
       Takes  a screenshot and saves it to the filename specified.  Note: screenshots can only be
       taken when a client is attached.

   xpra version
       Queries the server version and prints it out.  Note: older servers may  not  support  this
       feature.

   xpra info
       Queries  the  server  for  version,  status  and  statistics.  Note: older servers may not
       support this feature.

   xpra control
       Modify the server at runtime by issuing commands.  The list of commands can be obtained by
       specifying  "help"  as  command.   Some  of  those  commands  may  support  a  "help" mode
       themselves.

   xpra initenv
       This internal command creates the run-xpra script used with ssh connections.

   xpra stop
       This command  attaches  to  a  running  xpra  server,  and  requests  that  it  terminates
       immediately.   This  generally  causes  any applications using that server to terminate as
       well.

   xpra exit
       This command  attaches  to  a  running  xpra  server,  and  requests  that  it  terminates
       immediately.  Unlike xpra stop, the Xvfb process and its X11 clients (if any) will be left
       running.

   xpra showconfig
       This commands shows the configuration which would be used given  the  arguments  provided.
       You  can also specify as extra arguments the specific options that should be displayed, or
       use the special value all to display all the options including the ones which are normally
       not displayed because they are not relevant on the given system.

   xpra list
       This  command  finds  all  xpra  servers that have been started by the current user on the
       current machine, and lists them.

   xpra upgrade
       This command starts a new xpra server,  but  instead  of  creating  it  from  scratch,  it
       attaches  to  another  existing  server,  tells  it  to  exit, and takes over managing the
       applications that it was managing before.  As the name suggests, the main use case  is  to
       replace  a  server  running against an older version of xpra with a newer version, without
       having to restart your session.  Any currently-running xpra attach command will  exit  and
       need to be restarted.

   xpra shadow
       This  command shadows an existing X11 display. If there is only one X11 display active and
       its number is below 10, it can be auto-detected.

       Note that this mode of operation uses screenscraping which is far less efficient. Using  a
       video encoder (h264 or vp8) is highly recommended for this mode of operation.

   xpra proxy
       This  command allows a single server to proxy connections for multiple others, potentially
       serving as a load balancing or authentication entry point for many  sessions.   The  proxy
       server  will spawn a new process for each proxy connection, this proxy process will create
       an unauthenticated new unix domain socket which can be used  with  the  subcommands  info,
       version and stop.

   Important Note
       Some  platforms  and  package  managers  may  choose  to only build the client and not the
       server. In this case, only the attach subcommand will be available.

OPTIONS

   General options
       --version
              Displays xpra's version number.

       -h, --help
              Displays a summary of command line usage.

       -d FILTER1,FILTER2,..., --debug=FILTER1,FILTER2,...
              Enable debug logging.  The special value all enables all debugging.

       --mmap=yes|no|ABSOLUTEFILENAME
              Enable or disable memory mapped pixel data transfer.  By  default  it  is  normally
              enabled  automatically  if  the server and the client reside on the same filesystem
              namespace.  This method of data transfer offers much lower  overheads  and  reduces
              both  CPU  consumption  and  local  network  traffic.  When attaching, you can also
              specify an absolute path where the mmap file will be created.

       --windows=yes|no
              Enable or disable the forwarding of windows. This is usually the  primary  use  for
              xpra and should be enabled.

       --readonly=yes|no
              Read only mode ignores all keyboard and mouse activity.

       --clipboard=yes|no|clipboard-type
              Enable or disable clipboard synchronization.  If disabled on the server, no clients
              will be able to use clipboard synchronization at all. If turned off on the  client,
              only  this  particular connection will ignore clipboard data from the server.  This
              can also be used to specify a different clipboard  implementation.   The  clipboard
              types  available  will vary from platform to platform and also depend on build time
              environment and options so this is  best  left  on  auto.   Other  clipboard  types
              available may include:

              translated
                     Clipboard which can translate from one type of selection to another

              GDK    The most complete clipboard implementation, includes full X11 support

              default
                     Fallback clipboard, with limited X11 support

              OSX    OSX specific clipboard

       --clipboard-direction=to-server|to-client|both|disabled
              Choose the direction of the clipboard synchronization.

       --pulseaudio=yes|no
              Enable or disable the starting of a pulseaudio server with the session.

       --pulseaudio-command=SERVER-START-COMMAND
              Specifies  the  pulseaudio  command  to  use to start the pulseaudio server, unless
              disabled with pulseaudio=no.

       --session-name=VALUE
              Sets the name of this session. This value may be used in notifications,  utilities,
              tray  menu,  etc.   Setting this value on the server provides a default value which
              may be overridden on the client.

       --encoding=ENCODING
              This specifies the  image  encoding  to  use,  there  are  a  number  of  encodings
              supported:  jpeg,  png,  png/P, png/L, webp, rgb, vp8, vp9, h264 and h265 (some may
              not be available in your environment).  The default option is auto which allows the
              server to select the best encoding automatically.

              auto   default  mode:  the  built-in  heuristics  will  choose the most appropriate
                     encoding

              png    compressed and lossless, can be quite slow.

              png/P  compressed  and  lossy:  it  uses  a  colour  palette,  which  means  better
                     compression but still slow.

              png/L  compressed and lossy: grayscale only using a palette.

              rgb    a  raw  pixel  format  (lossless)  compressed  with  lz4,  lzo  or zlib (see
                     compressors) the compression ratio is lower, but it is by  far  the  fastest
                     encoding available.

              webp   can be used in lossy or lossless mode, useful for graphical applications, it
                     compresses  better  than  jpeg  and  is  reasonably  fast  except  at   high
                     resolutions.

              jpeg   can be useful for graphical applications, it is lossy and usually very fast.

              vp8    lossy video encoding which always uses colour subsampling.  Fast at encoding
                     and decoding.

              vp9    Video encoding which supports both lossy and lossless  modes,  available  if
                     your ffmpeg library version is recent enough.

              h264   One  of  the  best encoding available: it is fast, efficient and tunable via
                     the quality and speed options.

              h265   Far too slow at encoding, avoid.

       The default encoding which is automatically selected if you do not specify one will depend
       on  what  options are available on both the server and the client: rgb is always available
       (builtin), jpeg and png require the Python Imaging Library, vp8, vp9, webp, h264 and  h265
       all require their respective shared libraries, as well as the xpra codec that uses them.

       Note:  when selecting a video encoding (usually h264, vp8 or vp9), it will only be used if
       the screen is updating quickly enough, some of the smaller screen  updates  will  also  be
       sent using one of the other non-video encodings.

       --video-scaling=on|off|SCALING
              How  much  automatic  video  downscaling  should  be  used,  from 1 (rarely) to 100
              (aggressively), 0 to disable.  Video scaling is normally used with video regions or
              very  large  windows  (especially  full screen windows) to try to maintain a decent
              framerate.  Video downscaling negatively affects  visual  quality  and  will  cause
              automatic refreshes (if enabled), it is most useful on video content where it saves
              a considerable amount of bandwidth.

       --socket-dir=DIR
              Location where to write and look for the Xpra socket files.  The  default  location
              varies   from   platform  to  platform  ("~/.xpra"  on  most  Posix  systems).   If
              unspecified, the first value from  socket-dirs  will  be  used.   It  may  also  be
              specified using the XPRA_SOCKET_DIR environment variable.

              When  using  the socket-dir option, it is generally necessary to specify socket-dir
              or socket-dirs on all following commands, for xpra to work with the open sessions.

              By specifying a shared directory  this  can  be  coupled  with  the  mmap-group  or
              socket-permissions option to connect Xpra sessions across user accounts.

       --socket-dirs=DIR
              Specifies  the directories where to look for existing sockets if a specific one was
              not set using socket-dir.  You may specify each directory using a new --socket-dirs
              command  line argument, or joined together by the path separator (: on Posix).  The
              paths will be expanded.  (ie: --socket-dirs=~/.xpra:/tmp)

       --file-transfer=on|off
              Enable file transfers.

       --open-files=on|off
              This option may be used to allow the remote end to automatically open  files  after
              they  have  been  uploaded.   This  may be a security risk if you are using xpra to
              constrain what the clients can execute on the server.

       --forward-xdg-open=on|off
              Intercept execution of xdg-open and forward the request to the client.

       --open-command=COMMAND
              The command to use for opening files and URLs.

       --bandwidth-limit=BITSPERSECOND
              Restrict bandwidth usage to below the limit given.  The client's value cannot raise
              the  limit  of  the  server.   The value may be specified using standard units, ie:
              1Mbps or 500K.  In auto mode, the client will set the bandwidth limit value to  80%
              of the maximum speed of the network interface it is using to connect to the server.

          Options for start, start-desktop, upgrade, proxy and shadow

       --daemon=yes|no
              By default, the xpra server puts itself into the background, i.e. 'daemonizes', and
              redirects its output to a log file.  This can be  used  to  prevent  that  behavior
              (useful mostly for debugging).

       --chdir=DIR
              Change to this directory after daemonizing.

       --uid=UID and --gid=GID
              When  launching the server as root, these options can be used to drop privileges to
              the given UID / GID.

       --pidfile=FILENAME
              Writes the server process ID to this file on startup.  If the  file  has  not  been
              replaced, it will be deleted when the server exits.

       --bind=BIND_LOCATION
              Create  a local Unix domain socket (on Unix) or named-pipe (on MS Windows) for each
              bind option specified.

              This option can be specified multiple times to specify multiple  socket  locations.
              These  sockets  support  local  connections  with the :7-style display address, and
              remote connections with the ssh:frodo:7-style display address.

              Local sockets may also process HTTP / Websocket connections if the html  switch  is
              enabled.

              The location can take the form:

              none   do not create a socket

              auto   backwards compatible default which uses the current socket-dir

              DIRECTORY/
                     create  a socket in the directory specified, if the directory does not exist
                     then it will be created - you should include the trailing slash  to  prevent
                     the confusion with the PATH form:

              PATH   create the socket using the path specified

       --bind-tcp=[HOST]:PORT
              Create  a  TCP socket for each --bind-tcp option specified.  If the host portion is
              omitted,  then  127.0.0.1  (localhost)  will  be  used.   If  you  wish  to  accept
              connections on all interfaces, pass 0.0.0.0 for the host portion.

              Using  this  switch  without using the tcp-auth option is not recommended, and is a
              major security risk (especially when passing 0.0.0.0)!  Anyone at all  may  connect
              to this port and access your session.

              TCP  sockets  may  also  process HTTP / Websocket connections if the html switch is
              enabled.  TCP sockets may also be upgraded to SSL sockets  if  the  ssl  switch  is
              enabled.

       --bind-udp=[HOST]:PORT
              Create  a  UDP socket for each --bind-udp option specified.  If the host portion is
              omitted,  then  127.0.0.1  (localhost)  will  be  used.   If  you  wish  to  accept
              connections on all interfaces, pass 0.0.0.0 for the host portion.

              Using  this  switch  without using the udp-auth option is not recommended, and is a
              major security risk (especially when passing 0.0.0.0)!  Anyone at all  may  connect
              to  this  port  and  access  your  session.  UDP sessions are trivial to hijack for
              anyone able to sniff even just a single packet, it should  only  be  used  in  very
              specific use-cases, and never over unsecured networks.

       --bind-ws=[HOST]:PORT
              Create  an  HTTP  /  Websocket  listener.   See bind-tcp for host restrictions, you
              should use the auth-ws to secure access.

       --bind-wss=[HOST]:PORT
              Create an HTTPS / Secure Websocket listener.  See bind-tcp for  host  restrictions,
              you should use the auth-wss to secure access.

       --bind-ssl=[HOST]:PORT
              Just like --bind-tcp but for SSL sockets.  See ssl-auth and the other SSL options.

       --bind-rfb=[HOST]:PORT
              Listens  for  RFB  connections on the given port.  These sockets are only supported
              with the start-desktop and shadow modes.

       --bind-vsock=CID:PORT
              Create a VSOCK socket for each --bind-vsock option specified.

       --auth=MODULE[:OPTION=VALUE]
              Specifies the authentication module to use for unix domain  sockets  created  using
              the  bind  switch.  Authentication  modules  can  validate  a username and password
              against a variety of backend modules:

              allow  always allows authentication - this is dangerous and should only be used for
                     testing

              fail   always fails authentication, useful for testing

              env    matches against the environment variable specified by the name option (which
                     defaults to XPRA_PASSWORD).  ie: --auth=env:name=SOME_OTHER_ENV_VAR_NAME.

              password
                     matches  against  the  password  specified  using  the  value  option.   ie:
                     --auth=password:value=YOURPASSWORD.   Note:  this command line option may be
                     exposed to other processes on the same system.

              file   checks the password against the password data found in  the  file  specified
                     using the filename option.  ie: --auth=file:filename=./password.txt.

                     The  contents  of  this  file  will  be treated as binary data, there are no
                     restrictions on character encodings or file size.

              multifile
                     checks the username and  password  against  the  file  specified  using  the
                     filename option.  The file must contain each user credentials on one line of
                     the form:

                     username|password|uid|gid|displays|env_opts|session_opts

                     It is not possible to have usernames  or  password  that  contain  the  pipe
                     character | which is used as delimiter, or newlines and carriage returns.

              sqlite checks  the username and password against the sqlite database file specified
                     using the filename option.  The authentication will be processed  using  the
                     following  query  (which is configurable using the "password_query" option):
                     SELECT password FROM users WHERE username=(?)  The  sessions  available  for
                     each   user  will  be  querying  using:  (this  is  configurable  using  the
                     "sessions_query"  option):   SELECT   uid,   gid,   displays,   env_options,
                     session_options  FROM  users  WHERE  username=(?)   Multiple displays may be
                     specified as a comma separated list.

              hosts  checks the host using the system's tcp-wrappers library.  (Posix  only,  and
                     not available on Mac OS) See hosts.allow and hosts.deny for details.

              exec   Executes the command specified using the command attribute, the arguments to
                     this command are: a description of the access request and the timeout value.
                     (also  configurable) If the command is not specified, the system will try to
                     locate and use the auth_dialog utility which  is  shipped  with  xpra.   The
                     command should return 0 to allow access, any other value will deny access.

              peercred
                     checks  the  unix  domain  socket  peer credentials using SO_PEERCRED.  This
                     authentication module is only available on some  Posix  compliant  operating
                     systems.  This module will verify that the operating system provides the uid
                     and gid of the  process  that  initiated  the  connection.   Access  can  be
                     restricted  by  supplying in CSV format the list of valid uids and gids that
                     are allowed to connect.  Those id values may be  specified  using  numerical
                     values  or using the usernames / group names.  This module is different from
                     the others in that it will not require the client to supply  a  username  or
                     password,   as   those  are  ignored.   Environment  variables  and  pseudo-
                     environment   variables    may    also    be    used    as    values,    ie:
                     --auth=peercred:uid=\$UID.

              pam    validates the username and password using the PAM system

              win32  validates  the  username and password using Microsoft Windows authentication
                     (only available on this platform)

              sys    chooses the appropriate system authentication module  automatically  (either
                     pam or win32)

              kerberos-password
                     validates the username and password using kerberos authentication.  Warning:
                     this module does not use kerberos tickets and the password will be  sent  in
                     plain text to the server. This should only be used for testing.

              kerberos-ticket
                     validates a kerberos ticket obtained by the client.

              gss    validates a GSS ticket obtained by the client.

              u2f    requests a U2F token from the client.

              ldap   validates  the  username  and  password  against  an  LDAP server, using the
                     python-ldap library.

              ldap   validates the username and password against an LDAP server, using the python
                     ldap3 library.

       --tcp-auth=MODULE
              Just  like  the  auth  switch, except this one only applies to TCP sockets (sockets
              defined using the bind-tcp switch).

       --udp-auth=MODULE
              Just like the tcp-auth switch, except this one only applies to UDP sockets (sockets
              defined using the bind-udp switch).

       --ws-auth=MODULE
              Just  like  the  auth  switch,  except this one only applies to ws sockets: sockets
              defined using the bind-ws switch, or TCP sockets upgraded to  websockets.  (if  the
              htmlfP option is enabled).

       --wss-auth=MODULE
              Just  like  the  auth  switch, except this one only applies to wss sockets: sockets
              defined using the bind-wss switch, ws sockets upgraded to SSL (if the ssl option is
              enabled) or TCP sockets upgraded to SSL and then to wss.  (if both the ssl and html
              options are enabled).

       --ssl-auth=MODULE
              Just like the auth switch, except this one only applies  to  SSL  sockets:  sockets
              defined using the bind-ssl switch, or TCP sockets upgraded by ssl=auto or ssl=on.

       --rfb-auth=MODULE
              Authentication module to use for the bind-rfb sockets.

       --vsock-auth=MODULE
              Just  like  the auth switch, except this one only applies to VSOCK sockets (sockets
              defined using the bind-vsock switch).

       --challenge-handlers=MODULES
              Configures which challenge handlers are used by the client and in which order.  The
              default  value  is: all which corresponds to: uri,file,env,kerberos,gss,u2f,prompt.
              Note: some of these modules will fall through to  others  if  they  are  enable  to
              supply  the  challenge  requested (uri, file, kerberos and gss), others do not (env
              and prompt).

              uri    Use the password specified on the connection string, if any.

              file   Loads the password from the file specified with the password-file switch.

              env    Use the password specified using the XPRA_PASSWORD environment variable.

              kerberos
                     Request a kerberos token for the service specified.

              gss    Request a gss token for the service specified.

              u2f    Requests a token from a U2F device.

              prompt Prompt the user for the value.  Terminal clients prompt  using  text  input,
                     GUI clients use a dialog.

       --min-port=PORT
              The  minimum  port number allowed when creating UDP and TCP sockets.  You can use a
              lower value to allow unprivileged users to bind to privileged ports  when  starting
              sessions  via the system wide proxy server.  The default value is 1024 which is the
              standard value for privileged ports.

       --mdns=yes|no
              Enable or disable the publication of new sessions via mDNS.

       --dbus-launch=COMMAND|no
              Start the session within a dbus-launch context, you can  specify  the  dbus  launch
              command  to  use,  or  turn  it off completely.  Some features may not be available
              without a dbus context.

       --dbus-proxy=yes|no
              Allows the client to forward dbus calls to the server.

       --dbus-control=yes|no
              Start a dbus server which can be used to interact with the server process.

          Options for start, start-desktop, upgrade

       --start=CMD
              After starting the server, runs the command  CMD  using  the  default  shell.   The
              command  is  run  with its $DISPLAY set to point to the newly-started server.  This
              option may be given multiple times to start multiple commands.

       --start-child=CMD
              Identical  to  --start,  except  that  the  commands  are  taken  into  account  by
              --exit-with-children.

       --start-after-connect=CMD
              Wait for the first client to connect before starting the command.

       --start-child-after-connect=CMD
              Wait  for  the  first  client  to  connect  before starting the child command.  See
              start-child.

       --start-on-connect=CMD
              Execute this command every time a client connects.

       --start-child-on-connect=CMD
              Execute this child command every time a client connects.  See start-child.

       --terminate-children=yes|no
              On server stop, terminate all the child commands that  have  been  started  by  the
              server.  This  does  not  affect  server exit.  Most child commands are tied to the
              display so they are normally forced to shutdown anyway, but this  gives  them  more
              time  to  cleanup  properly and can be used to stop background commands that aren't
              tied to a display.

       --exit-with-children=yes|no
              This option may only be used if --start-child is also given.  If it is given,  then
              the  xpra  server will monitor the status of the children started by --start-child,
              and will automatically terminate itself when the last of them has exited.

       --exit-with-client=yes|no
              The server will terminate when the last client disconnects.

       --env=KEY=VALUE
              Extra environment variables which will only affect commands started using fB--start
              or --start-child.

       --start-new-commands=yes|no
              Allow  clients  to  ask the server to execute new commands.  (this can also be used
              via the control channel)

       --start-via-proxy=yes|no|auto
              If enabled, the start and start-desktop subcommands will be delegated to the system
              wide proxy server instance.  With auto mode, this delegation will only occur if the
              system wide proxy server is found.

       --systemd-run=yes|no|auto
              Wrap server start commands with systemd-run.

       --systemd-run-args=ARGS
              Command line arguments passed to systemd-run.

       --use-display
              Use an existing display rather than starting one with xvfb.   You  are  responsible
              for  starting  the  display  yourself.  This can also be used to rescue an existing
              display whose  xpra  server  instance  crashed  or  for  running  xpra  against  an
              accelerated X11 server.

       --displayfd=FD
              The  xpra  server  will  write the display number back on this file descriptor as a
              newline-terminated string.  This is most useful when  the  display  number  is  not
              specified with the xpra start or start-desktop subcommands.

       --xvfb=CMD
              When  starting a seamless server, xpra starts a virtual X server to run the clients
              on.  If your Xvfb is installed in a funny location, or you want to use  some  other
              virtual  X server, then this switch allows you to specify how to run your preferred
              X server executable.  The default value used depends on your  platform.   For  more
              information, see: https://xpra.org/Xdummy.html

       --sync-xvfb=DELAY
              The  windows  are normally only displayed on the client(s), they are not painted on
              the virtual display.  Some applications like screen recorders may want  to  capture
              the window contents, you can use this option to enable painting with a configurable
              delay (in milliseconds).  Warning: this extra painting is expensive and quite slow,
              which is why it is not enabled by default.

       --attach=yes|no|auto
              Once  the  server  has started, immediately connect a client to it.  With the value
              auto, a client is started for remote servers only. (servers specified via a network
              URI)

          Options for start, start-desktop, upgrade, shadow

       --tcp-proxy=HOST:PORT
              Specifies  the  address  to  which non-xpra packets will be forwarded.  This can be
              used to share the same TCP port with another TCP servers,  usually  a  web  server.
              xpra  clients  will  connect  as usual, but any client that does not speak the xpra
              protocol will be forwarded to the alternative server.

       --html=on|off|auto|webrootpath
              Respond to HTTP requests on the TCP  port(s)  and  local  sockets.   This  requires
              websockify  to  be  installed and at least one TCP or local socket to be configured
              using the matching bind option.  The auto mode  will  enable  support  if  all  the
              components  are  available.  By default the server will provide access to the HTML5
              client.  You can also specify your own web root path as argument.

       --rfb-upgrade=DELAY
              Allows RFB clients (ie: VNC) to connect to a plain  TCP  socket.   If  no  data  is
              received after DELAY seconds, the server will send a RFB handshake.  This option is
              only applicable to servers started in start-desktop or shadow modes.

       --video-encoders=ENCODERS
              Specifies the video encoders to try to load.  By default, all of them  are  loaded,
              but  one  may want to specify a more restrictive list of encoders.  Use the special
              value 'help' to get a list of options.  Use the value 'none' to not load any  video
              encoders.

       --csc-modules=MODULES
              Specifies  the  colourspace  conversion modules to try to load.  By default, all of
              them are loaded, but one may want to specify a more restrictive  list  of  modules.
              Use the special value 'help' to get a list of options.  Use the value 'none' to not
              load any colourspace conversion modules.

       --mmap-group
              Sets the mmap file's gid to match the socket file's gid and sets  the  mmap  file's
              permissions to 660.  This is necessary to share the mmap file across user accounts.

       --socket-permissions=ACCESS-MODE
              Specifies  the  permissions on the server socket.  Defaults to 600. This is ignored
              when mmap-group is enabled.

          Options for start, start-desktop, upgrade and attach

       --encryption=CIPHER
              Specifies the cipher to use for securing the connection  from  prying  eyes.   This
              option  requires  the  use  of  the  --encryption-keyfile  option.  The only cipher
              supported at present is AES, if the client requests encryption it will be  used  by
              both  the  client  and  server  for  all  communication  after the initial password
              verification, but only if the server supports this feature too.  Note: this feature
              has  not  been  extensively  reviewed and as it is it should not be considered safe
              from determined attackers.

       --tcp-encryption=CIPHER
              Just like the encryption switch, except  this  one  only  applies  to  TCP  sockets
              (sockets defined using the bind-tcp switch).

       --encryption-keyfile=FILENAME
              Specifies  the  key  to use with the encryption cipher specified with --encryption.
              The client and server must use the same keyfile contents.

       --tcp-encryption-keyfile=FILENAME
              Just like the encryption-keyfile switch,  except  this  one  only  applies  to  TCP
              sockets (sockets defined using the bind-tcp switch).

       --idle-timeout=IDLETIMEOUT
              The connection will be terminated if there is no user activity (mouse clicks or key
              presses) for the given amount of time (in seconds). Use the value 0 to disable this
              timeout.

       --server-idle-timeout=IDLETIMEOUT
              The  server  will  exit  if there are no active connections for the given amount of
              time (in seconds).  Use the value 0 to disable this timeout.

       --clipboard-filter-file=FILENAME
              Name of a file containing regular expressions, any clipboard data that matches  one
              of  these  regular expressions will be dropped.  Note: at present this only applies
              to copying from the machine where this option is used, not to it.

       --dpi=VALUE
              The 'dots per inch' value that client applications  should  try  to  honour.   This
              numeric  value  should  be  in the range 10 to 500 to be useful.  Many applications
              will only read this value when starting up, so connecting to  an  existing  session
              started with a different DPI value may not have the desired effect.

       --pixel-depth=VALUE
              When  starting  a  server,  this  switch controls the bits per pixel of the virtual
              framebuffer. Possible values: 0 (auto), 16, 24, 30.  When starting a  client,  this
              switch  controls  the picture rendering with the opengl backend: values higher than
              24 will enable deep color, the value 24 enables regular true color  rendering.  Use
              the  value 0 to let the client decide if the rendering will benefit from using deep
              color. (this is only supported on some Posix clients) Other values  should  not  be
              used.

       --cursors=yes|no
              Enable   or  disable  forwarding  of  custom  application  mouse  cursors.   Client
              applications may change the mouse cursor at any time,  which  will  cause  the  new
              cursor's pixels to be sent to the client each time.  This disables the feature.

       --notifications=yes|no
              Enable or disable forwarding of system notifications.  System notifications require
              the xpra server to have its own instance of a dbus  daemon,  if  it  is  missing  a
              warning will be printed on startup.  This switch disables the feature entirely, and
              avoids the warning.

       --input-method=METHOD
              Specify which input method  to  configure.   This  sets  a  number  of  environment
              variables  which  should  be  honoured by applications started with the start-child
              option.

              The following METHODs are currently supported:

              none   Disable input methods  completely  and  prevent  it  from  interfering  with
                     keyboard input. This is the default.

              keep   Keeps  the  environment  unchanged.  You  are responsible for ensuring it is
                     correct.

              xim    Enables the X Input Method.

              IBus   Enables the Intelligent Input Bus.

              SCIM   Enables the Smart Common Input Method.

              uim    Enables the Universal Input Method.

       Any other value will also be set up, but will trigger a warning.

       --xsettings=yes|no
              Enable or disable xsettings synchronization.  Xsettings  are  only  forwarded  from
              posix clients connecting to real posix servers (not shadows).

       --system-tray=yes|no
              Enable  or  disable  forwarding of system tray icons.  This feature requires client
              support and may not be available on all platforms.

       --bell=yes|no
              Enable or disable forwarding of the system bell.

       --webcam=yes|no
              Enable or disable webcam forwarding.

       --mousewheel=on|off|invert|invert-x|invert-y|invert-z
              Mouse wheel handling: can be used to disable mouse wheel forwarding  or  to  invert
              some or all axes.

       --remote-logging=yes|no|both
              Allow  the  client to forward its log output to the server.  The client can specify
              the value both to both send it to the server and keep it locally.

       --av-sync=yes|no
              Enable or disable audio-video synchronization.  The video data will be  delayed  so
              that  it  is  displayed  in  sync with the audio.  Note: this only applies to video
              regions, either auto-detected via the builtin heuristics  or  specified  using  the
              dbus interface.

   Options for attach
       --password-file=FILENAME
              Supply the password to be used for connecting to a server that uses authentication.
              See auth, tcp-auth, ssl-auth and vsock-auth for details.   Alternatively,  you  may
              use the XPRA_PASSWORD environment variable.

       --opengl=(yes|no|auto)[:backend]
              Use  OpenGL  accelerated  rendering on the client.  The default is to detect if the
              graphics card and drivers are supported (auto  mode),  but  one  can  also  disable
              OpenGL  (no)  or force it enabled (yes).  On some platforms, it is also possible to
              specify which backends should be used, only gtk and native are currently  supported
              and only on X11 platforms.  ie: opengl=yes:native, or opengl=auto:gtk,native.

       --webcam=yes|no|/dev/deviceXXX|DEVICEID
              Enable  or  disable  webcam  forwarding.   The  webcam  device  to  use can also be
              specified.

       -zLEVEL, --compress=LEVEL
              Select the level of compression xpra will  use  when  transmitting  data  over  the
              network.   With  the lz4 and lzo compressors, there are only two possible values: 0
              (meaning no compression) and 1 (compression enabled).  The zlib compressor supports
              values  between 0 (meaning no compression) and 9, inclusive. It should only be used
              when lz4 and lzo are not available.

              This compression is not used on pixel data (except when using the rgb encoding).

       --quality=VALUE
              This option sets a fixed image compression quality for lossy encodings (jpeg, webp,
              h264/h265  and  vp8/vp9).  First, one of those lossy encodings must be enabled with
              --encoding.  Values range from 1 (lowest  quality,  high  compression  -  generally
              unusable)  to  100  (highest quality, low compression).  Specify a value of zero to
              let the system tune the quality dynamically to achieve  the  best  bandwidth  usage
              possible.  It is usually best not to use this option and use min-quality instead.

       --min-quality=MIN-QUALITY
              This  option  sets  the minimum encoding quality allowed when the quality option is
              set to automatic mode.

       --speed=SPEED
              This option sets the encoding speed.  Slower  compresses  more,  faster  will  give
              better  latency.   The  system normally uses a variable speed, this option forces a
              fixed speed setting to be used instead.  It is usually best not to use this  option
              and use min-speed instead.

       --min-speed=MIN-SPEED
              This option sets the minimum encoding speed allowed when the speed option is set to
              automatic mode.

       --auto-refresh-delay=DELAY
              This option sets a delay after which the windows are automatically refreshed  using
              a  lossless  frame.   The delay is a floating-point number and is in seconds.  This
              option is enabled by default with a delay of 0.25 seconds.   This  option  is  only
              relevant when using a lossy encoding.

       --shortcut-modifiers=MODIFIERS
              Defines the default shorcut modifers required by the key-shortcuts, these modifiers
              can then be referred to as #.  The default  value  is  'auto'  which  evaluates  to
              Meta+Shift on most platforms.

       --key-shortcut=KEY:ACTION
              Can  be specified multiple times to add multiple key shortcuts.  These keys will be
              caught by the client and trigger the action specified and the key presses will  not
              be passed on to the server.

              The  KEY  specification may include keyboard modifiers in the form [modifier+]*key,
              for example: Shift+F10 or Shift+Control+B.  You can refer to  the  shorcut-modifers
              option value using #, ie: #+F1.

              If  no  shortcuts are defined on the command line, the default builtin list will be
              used.

              Some of the actions may allow arguments (ie: the log action does),  in  which  case
              they are specified in the usual programming style syntax: ACTION(ARG1, ARG2, etc)
              String  arguments  must be quoted (both single and double quotes are supported) and
              numeric arguments must not be quoted.  Beware the the parenthesis and  quotes  must
              usually  be  escaped  when  used  from  a  shell  command  line.   Example:  --key-
              shortcut=Meta+Shift+F7:log\(\'hello\'\)

              The following ACTIONs are currently defined:

              quit   Disconnect the xpra client.

              log("MESSAGE")
                     Sends MESSAGE to the log.

              show_session_info[("TabName")]
                     Shows the session  information  window.  The  optional  TabName  allows  the
                     information  tab shown to be selected. Use the value help to get the list of
                     options.

              show_menu
                     Shows the menu normally found in the system tray.

              show_start_new_command
                     Shows the start new command dialog.

              magic_key
                     Placeholder which can be used by some client toolkits.

              void   Does not do anything, and can therefore  be  used  to  prevent  certain  key
                     combinations from ever being sent to the server.

              refresh_window
                     Force the currently focused window to be refreshed.

              refresh_all_windows
                     Force all windows to be refreshed.

              toggle_keyboard_grab
                     The keyboard will be grabbed / ungrabbed by the current window.

              toggle_pointer_grab
                     The pointer will be grabbed and confined to the current window.

              toggle_fullscreen
                     Make the current window fullscreen / unfullscreen.

              toggle_debug
                     Turn debugging on or off.

              scaleup
                     Increase the current value of desktop-scaling.

              scaledown
                     Decrease the current value of desktop-scaling.

              scalereset
                     Reset the desktop-scaling to its original value.

              scalingoff
                     Turn off desktop-scaling.

              increase_quality
                     Increase  the  min-quality or quality setting (whichever one is currently in
                     use).

              decrease_quality
                     Decrease the min-quality or quality setting (whichever one is  currently  in
                     use).

              increase_speed
                     Increase the min-speed or speed setting (whichever one is currently in use).

              decrease_speed
                     Decrease the min-speed or speed setting (whichever one is currently in use).

       --sharing=yes|no|auto
              Sharing  allows  more than one client to connect to the same session.  This must be
              enabled on both the server and all co-operating clients  to  function.   When  used
              server-side,  the  default  value  auto  allows  the  clients to decide if they are
              willing to share the session.   When  used  client-side,  the  default  value  auto
              evaluates to no.

       --lock=yes|no|no
              Locking  allows  a  client to refuse to hand over the session to a new client.  The
              session may still be shared with multiple clients (see  the  sharing  option),  but
              otherwise  the  server will reject new clients.  When used server-side, the default
              value auto allows the clients to decide if they want to  lock  the  session.   When
              used client-side, the default value auto evaluates to no.

       --keyboard-sync=yes|no
              Normally  the  key  presses  and  key release events are sent to the server as they
              occur so that the server can  maintain  a  consistent  keyboard  state.   Disabling
              synchronization  can prevent keys from repeating unexpectedly on high latency links
              but it may also disrupt applications which access  the  keyboard  directly  (games,
              etc.).

       --keyboard-raw=yes|no
              Tells  the  server to process all keyboard input untranslated.  Both the client and
              the server must be using the same type of keyboard interface. (ie: both using X11)

       --keyboard-layout=LAYOUTSTRING
              The keyboard layout is normally detected automatically.  This option overrides it.

       --keyboard-layouts=LAYOUTS
              The list of keyboard layouts to enable.

       --keyboard-variant=VARIANT
              Override for the keyboard layout variant.

       --keyboard-variants=VARIANTS
              Override for the keyboard layout variants.

       --keyboard-options=OPTIONS
              Override for the keyboard options sent to the server.

       --swap-keys=YES|NO
              This option only applies to MacOS clients, it swaps the command  and  control  keys
              and is enabled by default.

       --sound-source=PLUGIN
              Specifies  the  GStreamer  sound  plugin used for capturing the sound stream.  This
              affects "speaker forwarding" on the server,  and  "microphone"  forwarding  on  the
              client.   To  get  a  list  of  options  use  the special value 'help'.  It is also
              possible  to  specify  plugin  options  using  the  form:   --sound-source=   pulse
              device=device.alsa_input.pci-0000_00_14.2.analog-stereo

       --speaker=on|off|disabled and --microphone=on|off|disabled|on:DEVICE|off:DEVICE
              Sound  input and output forwarding support: on will start the forwarding as soon as
              the connection is established, off will require the user to enable it via the menu,
              disabled will prevent it from being used and the menu entry will be disabled.  With
              microphone forwarding, you may also be able to specify which device to use.

       --speaker-codec=CODEC and --microphone-codec=CODEC
              Specify the codec(s) to use for sound output (speaker) or input (microphone).  This
              parameter  can  be  specified  multiple times and the order in which the codecs are
              specified defines the preferred codec order.  Use the special value 'help' to get a
              list  of  options.   When unspecified, all the available codecs are allowed and the
              first one is used.

       --title=VALUE
              Sets the text shown as window title.  The string supplied can make  use  of  remote
              metadata  placeholders  which will be populated at runtime with the values from the
              remote server.  The default value used is "@title@ on @client-machine@".

              The following placeholders are defined:

              @title@
                     Will be replaced by the remote window's title.

              @client-machine@
                     Will be replaced by the remote server's hostname.

       --border=BORDER
              Specifies the color and size of the border to draw inside every xpra window.   This
              can  be  used to easily distinguish xpra windows running on remote hosts from local
              windows.  The BORDER can be specified using  standard  color  names  (ie:  red,  or
              orange)  or  using  the  web  hexadecimal syntax (ie: #F00 or #FF8C00). The special
              color name "auto" will derive  the  color  from  the  server  target  address  (the
              connection  string)  so  that  connecting to the same target should always give the
              same color.   You  may  also  specify  the  size  of  the  border  in  pixels,  ie:
              --border=yellow,10.

       --window-icon=FILENAME
              Path  to  the  default  image which will be used for all windows.  This icon may be
              shown in the window's bar, its iconified state or task switchers.  This depends  on
              the operating system, the window manage and the application may override this too.

       --window-close=ACTION
              Choose  what action to take when the window is closed by the client.  The following
              actions can be used:

              auto   The client will figure out what is best based on the window type.   This  is
                     the  default.   ie:  it  will  use  disconnect shadow sessions, Iforward for
                     seamless windows.

              forward
                     The event will be forwarded to the server.

              ignore Do nothing.

              disconnect
                     Disconnect from the server.

              shutdown
                     Shutdown the server.

       --desktop-scaling=off|on|auto|VALUE
              Desktop scaling allows the windows to be scaled by the  client.   Downscaling  will
              mostly  waste  bandwidth,  upscaling allows the window's pixels to be sent over the
              wire at a lower resolution, saving bandwidth and CPU time.  This option can also be
              used  to  request  a  specific  scaling value.  For best results, use opengl client
              rendering, the other display backends  may  show  visual  artifacts  when  scaling.
              Note:  the  scaling  may  also be adjusted at runtime through keyboard shortcuts if
              those are configured.

              The desktop-scaling value can take the form:

              off    scaling will be disabled

              on     scaling will be allowed, but it will start unscaled

              auto   scaling will be allowed and a scaling value will be automatically chosen  if
                     the  client's  desktop  is  large  (bigger  desktops will use higher scaling
                     values)

              scaling-value
                     scaling will be enabled and use the given  value,  specified  as  a  number,
                     fraction or percentage. ie: 2, 3/2 or 150%.

              pair   the  scaling will be enabled and use a different value for the X and Y axis.
                     ie: 3x2 or 3/2x4/3

              desktop-size
                     the scaling will be enabled and the server will render to  the  given  size.
                     ie: 1600x1200

       --tray=yes|no Enable or disable the system tray.  Not available on OSX since the dock icon
       is always shown.

       --delay-tray
              Waits for the first window or notification to  appear  before  showing  the  system
              tray. (posix only)

       --tray-icon=FILENAME
              Specifies  the  icon  shown  in the dock/tray.  By default it uses a simple default
              'xpra' icon.  (On Microsoft Windows, the icon must be in ico format.)

       --enable-pings
              The client and server will exchange ping and echo packets which are used to  gather
              latency statistics.  Those statistics can be seen using the xpra info command.

   Options for attach, stop, info, screenshot, version
       --ssh=CMD
              When  you  use  an ssh: address to connect to a remote display, xpra runs ssh(1) to
              make the underlying connection. By default, it does this  by  running  the  command
              "ssh".  If  your ssh program is in an unusual location, has an unusual name, or you
              want to pass special options to change ssh's behavior, then you can use  the  --ssh
              switch to tell xpra how to run ssh.

              For example, if you want to use arcfour encryption, then you should run

                     xpra attach --ssh="ssh -c arcfour" ssh:frodo:7

              Note:  Don't  bother  to  enable ssh compression; this is redundant with xpra's own
              compression, and will just waste your CPU.  See also xpra's --compress switch.

              On MS Windows, where backslashes are used  to  separate  path  elements  and  where
              spaces  are  often used as part of paths, you need to add quotes around paths. (ie:
              ssh="C:\Program Files\Xpra\Plink.exe" -ssh -agent)

       --exit-ssh=yes|no
              Choose whether the SSH client process  should  be  forcibly  terminated  when  xpra
              disconnects from the server.  If you are using SSH connection sharing, you may want
              to avoid stopping the SSH master process instance spawned by xpra as it may be used
              by  other  SSH  sessions.   Note: the exit-ssh=no detaches the SSH process from the
              terminal which prevents the SSH process from interacting with the  terminal  input,
              this  disables  the  keyboard  interaction  required  for  password input, host key
              verification, etc..

       --remote-xpra=CMD
              When connecting to a remote server over ssh, xpra needs to be able to find and  run
              the  xpra  executable  on the remote host.  If this executable is in a non-standard
              location, or requires special environment variables to be set before  it  can  run,
              then  accomplishing  this may be non-trivial.  If running xpra attach ssh:something
              fails because it cannot find the remote xpra, then  you  can  use  this  option  to
              specify how to run xpra on the remote host.

              That  said,  this  option should not be needed in normal usage, as xpra tries quite
              hard to work around the above problems.  If you find  yourself  needing  it  often,
              then that may indicate a bug that we would appreciate hearing about.

   SSL Options
       --ssl=on|auto|off|tcp|www
              Whether  to  enable  SSL on TCP sockets and for what purpose.  The TCP sockets will
              automatically be upgraded to SSL when SSL packets are received.

              auto   The server will try  to  guess  what  protocol  to  use  for  each  new  SSL
                     connection: either xpra's native protocol or https / websocket (wss)

              tcp    The SSL sockets will only be used for xpra's native protocol

              www    The SSL sockets will only be used for https and websocket (wss)
       If SSL is enabled, then a ssl-cert is required.  Authentication, if required, will use the
       ssl-auth module specified, and fallback to tcp-auth or  auth  unless  the  value  none  is
       specified.

       The  remaining  options  mirror  the  Python  ssl module attributes.  Please refer to that
       documentation and bear in mind that configuring SSL  for  security  is  not  trivial,  and
       definitely      not      just      a      matter      of      enabling      SSL.      See:
       https://docs.python.org/2/library/ssl.html Some options may not be  available  with  older
       versions of Python.

       Summary: --ssl-key=KEYFILE The key file to use.

       --ssl-cert=ERTFILEORDIR
              Certificate file, required for server SSL support.

       --ssl-protocol=PROTOCOLVERSION
              Specifies which version of the SSL protocol to use.

       --ssl-ca-certs=CACERTSFILE
              The  ca_certs  file  contains  a  set  of  concatenated  'certification  authority'
              certificates. If a directory is specified, it should contain the certificates.

       --ssl-ca-data=ERTDATA
              Certificate data.

       --ssl-ciphers=CIPHERS
              Sets the available ciphers, it should be  a  string  in  the  OpenSSL  cipher  list
              format.

       --ssl-client-verify-mode=none|optional|required
              Whether  to  try  to  verify  the  client's  certificates  and  how  to  behave  if
              verification fails.

       --ssl-server-verify-mode=none|optional|required
              Whether  to  try  to  verify  the  server's  certificates  and  how  to  behave  if
              verification fails.

       --ssl-verify-flags=FLAGS
              The flags for certificate verification operations.

       --ssl-check-hostname=yes|no
              Whether to match the peer cert's hostname.

       --ssl-options=options
              Set of SSL options enabled on this context.

       ENVIRONMENT

       DISPLAY
              xpra  start --start-child=... sets this variable in the environment of the child to
              point to the xpra display.

              xpra attach, on the other hand, uses this variable to determine which  display  the
              remote applications should be shown on.

              fIXPRA_PASSWORD may be used with xpra attach instead of the password-file option.

FILES

       xpra.conf stores default values for most options.  There is a global configuration file in
       /etc or /usr/local/etc, and each user may override those defaults  by  creating  the  file
       .xpra/xpra.conf.   You can also split the options into multiple files by placing them in a
       conf.d directory with the .conf extension.  Xpra uses the directory  ~/.xpra  to  store  a
       number of files.  (The examples below are given for the display :7.)

       ~/.xpra/:7
              The  unix  domain socket that clients use to contact the xpra server, if the system
              configuration uses this directory.

       ~/.xpra/:7.log
              When run in daemon mode (the default), the xpra server directs all output  to  this
              file.  This includes all debugging output, if debugging is enabled.

       ~/.xpra/run-xpra
              A  shell script that, when run, starts up xpra with the correct python interpreter,
              PYTHONPATH, PATH, location of the main xpra script, etc.   Automatically  generated
              by  xpra  initenv,  xpra  start and used by xpra attach (see also the discussion of
              --remote-xpra).

BUGS

       Xpra has no test suite.

       Xpra does not fully handle all aspects of  the  X  protocol;  for  instance,  fancy  input
       features  like  pressure-sensitivity  on  tablets, some window manager hints, and probably
       other more obscure parts of the X protocol.  It does,  however,  degrade  gracefully,  and
       patches for each feature would be gratefully accepted.

       The  xpra  server allocates an over-large framebuffer when using Xvfb; this wastes memory.
       If the Xvfb does not support RandR this can also cause applications to misbehave (e.g.  by
       letting  menus  go  off-screen).  This is not a problem when using Xdummy, see the --xvfb=
       switch for details.  Conversely, if the framebuffer is ever insufficiently large,  clients
       will misbehave in other ways (e.g., input events will be misdirected).

REPORTING BUGS

       Send any questions or bugs reports to http://xpra.org/trac/

SEE ALSO

       screen(1) winswitch_applet(1)

                                                                                          XPRA(1)