Manual Pages for UNIX Operating System command usage for man xhost

User Commands                                            XHOST(1)



NAME
     xhost - server access control program for X

SYNOPSIS
     /usr/bin/xhost [[+-]name ...]

DESCRIPTION
     The xhost program is used to add and delete  host  names  or
     user  names to the list allowed to make connections to the X
     server.  In the case of hosts, 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 implement the  user-based
     mechanism or use the hooks in the protocol for passing other
     authentication data to the server.

OPTIONS
     Xhost accepts the following command line  options  described
     below.  For security, the options that affect access control
     may only be run from the "controlling host".   For  worksta-
     tions, this is the same machine as the server.  For X termi-
     nals, it is the login host.

     -help   Prints a usage message.

     [+]name The given name (the plus sign is optional) is  added
             to the list allowed to connect to the X server.  The
             name can be a host name or a user name.

     -name   The given name is removed from the list  of  allowed
             to  connect  to  the server.  The name can be a host
             name or a user name.  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 connec-
             tions) is the only way to  allow  local  connections
             again.

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

     -       Access is restricted  to  only  those  on  the  list
             (i.e., access control is turned on).

     nothing If no command line arguments are  given,  a  message
             indicating   whether   or   not  access  control  is
             currently enabled is printed, followed by  the  list
             of  those  allowed  to  connect.   This  is the only
             option that may be used from machines other than the



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User Commands                                            XHOST(1)



             controlling host.

NAMES
     A complete name has the  syntax  ``family:name''  where  the
     families are as follows:

     inet      Internet host (IPv4)
     inet6     Internet host (IPv6)
     dnet      DECnet host
     nis       Secure RPC network name
     krb       Kerberos V5 principal
     local     contains only one name, the empty string
     si        Server Interpreted

     The family is case insensitive.   The  format  of  the  name
     varies with the family.

     When Secure RPC is being used, the network independent  net-
     name  (e.g., "nis:unix.uid@domainname") can be specified, or
     a local user can be specified with just the username  and  a
     trailing at-sign (e.g., "nis:pat@").

     For backward compatibility with  pre-R6  xhost,  names  that
     contain  an at-sign (@) are assumed to be in the nis family.
     Otherwise they are assumed to be Internet addresses. If com-
     piled  to  support  IPv6,  then  all IPv4 and IPv6 addresses
     returned by getaddrinfo(3) are added to the access  list  in
     the appropriate inet or inet6 family.

     Server interpreted addresses  consist  of  a  case-sensitive
     type  tag and a string representing a given value, separated
     by a colon.  For example, "si:hostname:almas"  is  a  server
     interpreted address of type hostname, with a value of almas.
     For more information on the available forms of server inter-
     preted addresses, see the Xsecurity(5) manual page.

DIAGNOSTICS
     For each name added to the access control list,  a  line  of
     the  form  "name  being  added  to  access  control list" is
     printed.  For each name  removed  from  the  access  control
     list,  a  line  of  the form "name being removed from access
     control list" is printed.

FILES
     /etc/X*.hosts

SEE ALSO
     X(5), Xsecurity(5), Xserver(1),  xdm(1),  xauth(1),  netser-
     vices(1), getaddrinfo(3)

ENVIRONMENT
     DISPLAY to get the default host and display to use.



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User Commands                                            XHOST(1)



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).

     The X server  stores  network  addresses,  not  host  names,
     unless you use the server-interpreted hostname type address.
     If somehow you change a host's  network  address  while  the
     server is still running, and you are using a network-address
     based form of authentication, xhost must be used to add  the
     new address and/or remove the old address.

WARNINGS
     Oracle Solaris is secure by default.  See  Xserver(1)  which
     details  how to re-enable remote connections to the X server
     as in previous releases.

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


ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | x11/x11-server-utilities    |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|





















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