ZEPHYRD(8)                                             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 informa-
       tion.

       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  ini-
       tialization  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  informa-
       tion.
       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 subscrip-
       tion 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 enumer-
       ating 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

ZEPHYRD(8)                                             ZEPHYRD(8)

       authenticated.  The class 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 Authoriza-
       tion 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 redistri-
       bution.