ZEPHYRD(8) MIT Project Athena (July 1, 1988) ZEPHYRD(8)
NAME
zephyrd - Zephyr server daemon
SYNOPSIS
/usr/etc/zephyrd [ -d ]
DESCRIPTION
zephyrd is the central server for the Zephyr Notification
System. It maintains a location database of all currently
logged-in users, and a subscription database for each user's
Zephyr clients.
zephyrd communicates with daemons running on other Zephyr
server hosts, to provide a reliable service.
While running, any unusual conditions are recorded via
syslog(3) to facility local6 at various levels. The -d
option enables logging of additional debugging information.
When a zephyrd is executed, it requests a list of server
machines from Hesiod and initializes its state from any
zephyrds executing on the other known servers. This
initialization is only performed after the zephyrds have
authenticated themselves to each other via Kerberos. The
server then enters a dispatch loop, servicing requests from
clients and other servers.
SIGNALS
SIGUSR1 enables logging of additional debugging information.
SIGUSR2 disables the logging of additional debugging
information.
SIGHUP causes zephyrd to re-read the default subscription
file and to re-query Hesiod about valid peers. Any peers
which are not responding and no longer mentioned in Hesiod
are flushed; any peers not previously named by Hesiod are
added.
SIGINT and SIGTERM cause zephyrd to gracefully shut down.
SIGFPE causes zephyrd to dump the location and subscription
databases to /usr/tmp/zephyr.db in an ASCII format.
ACCESS CONTROL
Certain notice classes are restricted by the Zephyr server.
Each such class has access control lists enumerating who may
transmit (xmt-*.acl) or subscribe to that particular class.
Subscriptions may be restricted either absolutely (sub-*.acl
files), or by instance restrictions. iws-*.acl files
control subscriptions to wildcarded instances. iui-*.acl
files control subscriptions to instances which are not the
Kerberos principal identity of the subscriber. If an access
control list of a given type is absent, there is no
restriction of that type on the class, except that any
notices of the class must be authenticated. The class
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ZEPHYRD(8) MIT Project Athena (July 1, 1988) ZEPHYRD(8)
registry lists all classes which are restricted.
FILES
/usr/athena/lib/zephyr/class-registry.acl:
List of classes which are restricted
/usr/athena/lib/zephyr/iws-*.acl:
Access Control Lists for instance-wildcard
restrictions
/usr/athena/lib/zephyr/iui-*.acl:
Access Control Lists for instance-identity
restrictions
/usr/athena/lib/zephyr/sub-*.acl:
Access Control Lists for subscribing
/usr/athena/lib/zephyr/xmt-*.acl:
Access Control Lists for transmitting
/usr/athena/lib/zephyr/srvtab:
Kerberos Service keys
/usr/athena/lib/zephyr/ztkts:
Current Kerberos tickets for exchange with other
servers
/usr/tmp/zephyr.db:
File containing an ASCII dump of the database.
BUGS
The current implementation of the Zephyr server (zephyrd(8))
makes no distinction between realm-announced, net-visible
and net-announced exposure levels.
SEE ALSO
zephyr(1), zhm(8), kerberosintro(1), hesiod(3),
access_control_lists(?), syslog(3)
Athena Technical Plan, Sections E.4.1 (Zephyr Notification
Service) and E.2.1 (Kerberos Authentication and
Authorization System)
AUTHOR
John T. Kohl, MIT Project Athena and Digital Equipment
Corporation
RESTRICTIONS
Copyright (c) 1987,1988 by the Massachusetts Institute of
Technology. All Rights Reserved.
zephyr(1) specifies the terms and conditions for
redistribution.
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