xhost - server access control program for X
xhost [[[+-?name ...]
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.
Xhost accepts the following command line options described below. For security, the options that effect access control may only be run from the "controlling host". For workstations, this is the same machine as the server. For X terminals, it is the login host.
The family is case insensitive. The format of the name varies with the family.
When Secure RPC is being used, the network independent netname (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 the inet family is assumed.
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.
DISPLAY to get the default host and display to use.
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. This is not really a bug. If somehow you change a host's network address while the server is still running, xhost must be used to add the new address and/or remove the old address.
Bob Scheifler, MIT Laboratory for Computer Science, Jim Gettys, MIT Project Athena (DEC).