AHOST(1)

NAME
ahost - server access control program for AF

SYNOPSIS
ahost [[+-]hostname ...]

DESCRIPTION
The ahost program is used to add and delete hosts to the list of machines that are allowed to make connections to the AF 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.

The server initially allows network connections only from programs running on the same machine or from machines listed in the file /etc/AF*.hosts (where * is the device number of the server). The ahost 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
Ahost 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 AF 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. There is currently no way to break all existing connections.

+   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/AF*.hosts

SEE ALSO
AF(1)

ENVIRONMENT

AUDIOFILE
    to get the default host and server to use.

BUGS

COPYRIGHT
Copyright 1988, Massachusetts Institute of Technology. Copyright 1991-1994, Digital Equipment Corporation.
See AF(1) for a full statement of rights and permissions.

AUTHORS
Bob Scheifler, MIT Laboratory for Computer Science,
Jim Gettys, MIT Project Athena (DEC),
Win Treese, Cambridge Research Lab, Digital Equipment Corporation.