xhost(1) — bsd

XHOST(1)                             BSD                              XHOST(1)



NAME
     xhost - server access control program for X

SYNOPSIS
     xhost [[+-]hostname ...]

DESCRIPTION
     The xhost program is used to add and delete hosts to the list of machines
     that are allowed to make connections to the X server.  This provides a
     rudimentary form of privacy control and security.  It is only sufficient
     for a workstation (single user) environment, although it does limit the
     worst abuses.  Environments which require more sophisticated measures
     should use the hooks in the protocol for passing authentication data to
     the server.

     The server initially allows network connections only from programs
     running on the same machine or from machines listed in the file
     /etc/X*.hosts (where * is the display number of the server).  The xhost
     program is usually run either from a startup file or interactively to
     give access to other users.

     Hostnames that are followed by two colons (::) are used in checking
     DECnet connections; all other hostnames are used for TCP/IP connections.

OPTIONS
     Xhost accepts the following command line options described below.  For
     security, the options that effect access control may only be run from the
     same machine as the server.

     [+]hostname
             The given hostname (the plus sign is optional) is added to the
             list of machines that are allowed to connect to the X server.

     -hostname
             The given hostname is removed from the list of machines that are
             allowed to connect to the server.  Existing connections are not
             broken, but new connection attempts will be denied.  Note that
             the current machine is allowed to be removed; however, further
             connections (including attempts to add it back) will not be
             permitted.  Resetting the server (thereby breaking all
             connections) is the only way to allow local connections again.

     +       Access is granted to everyone, even if they aren't on the list of
             allowed hosts (i.e. access control is turned off).

     -       Access is restricted to only those machines on the list of
             allowed hosts (i.e. access control is turned on).

     nothing If no command line arguments are given, the list of hosts that
             are allowed to connect is printed on the standard output along
             with a message indicating whether or not access control is
             currently enabled.  This is the only option that may be used from
             machines other than the one on which the server is running.

FILES
     /etc/X*.hosts

SEE ALSO
     X(1), Xserver(1)

ENVIRONMENT

     DISPLAY to get the default host and display to use.

BUGS
     You can't specify a display on the command line because -display is a
     valid command line argument (indicating that you want to remove the
     machine named ``display'' from the access list).

COPYRIGHT
     Copyright 1988, Massachusetts Institute of Technology.
     See X(1) for a full statement of rights and permissions.

AUTHORS
     Bob Scheifler, MIT Laboratory for Computer Science,
     Jim Gettys, MIT Project Athena (DEC).

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