NAME

       zephyrd - Zephyr server daemon

SYNOPSIS

       /usr/sbin/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 /var/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 registry lists all classes which are restricted.

FILES

       /etc/zephyr/acl/class-registry.acl:
                 List of classes which are restricted

       /etc/zephyr/acl/iws-*.acl:
                 Access Control Lists for instance-wildcard restrictions

       /etc/zephyr/acl/iui-*.acl:
                 Access Control Lists for instance-identity restrictions

       /etc/zephyr/acl/sub-*.acl:
                 Access Control Lists for subscribing

       /etc/zephyr/acl/xmt-*.acl:
                 Access Control Lists for transmitting

       /etc/zephyr/srvtab:
                 Kerberos 4 Service keys

       /etc/zephyr/krb5.keytab:
                 Kerberos V Service keys

       /var/run/zephyrd.tkt4:
                 Current Kerberos 4 tickets for exchange with other servers

       /var/run/zephyrd.tkt:
                 Current Kerberos 5 tickets for exchange with other servers

       /var/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.