Provided by: zephyr-server_3.1.2-1build3_amd64 bug


       zephyrd - Zephyr server daemon


       /usr/sbin/zephyrd [ -d ]


       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.


       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.


       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.


                 List of classes which are restricted

                 Access Control Lists for instance-wildcard restrictions

                 Access Control Lists for instance-identity restrictions

                 Access Control Lists for subscribing

                 Access Control Lists for transmitting

                 Kerberos 4 Service keys

                 Kerberos V Service keys

                 Current Kerberos 4 tickets for exchange with other servers

                 Current Kerberos 5 tickets for exchange with other servers

                 File containing an ASCII dump of the database.


       The  current implementation of the Zephyr server (zephyrd(8)) makes no distinction between
       realm-announced, net-visible and net-announced exposure levels.


       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)


       John T. Kohl, MIT Project Athena and Digital Equipment Corporation


       Copyright  (c)  1987,1988  by  the  Massachusetts  Institute  of  Technology.   All Rights
       zephyr(1) specifies the terms and conditions for redistribution.