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NAME

       kerberos - introduction to the Kerberos system

DESCRIPTION

       The  Kerberos  system  authenticates  individual  users  in  a  network
       environment.  After authenticating yourself to Kerberos,  you  can  use
       network  utilities  such  as  rlogin,  rcp,  and  rsh without having to
       present passwords to remote hosts and without  having  to  bother  with
       .rhosts  files.   Note that these utilities will work without passwords
       only if the remote machines you deal with support the Kerberos  system.

       If you enter your username and kinit responds with this message:

       kinit(v5):  Client not found in Kerberos database while getting initial
       credentials

       you haven’t been registered  as  a  Kerberos  user.   See  your  system
       administrator.

       A  Kerberos  name  usually  contains  three  parts.   The  first is the
       primary, which is usually a user’s or service’s name.   The  second  is
       the  instance, which in the case of a user is usually null.  Some users
       may have privileged instances, however, such as ‘‘root’’ or  ‘‘admin’’.
       In  the  case of a service, the instance is the fully qualified name of
       the machine on which it runs; i.e.  there  can  be  an  rlogin  service
       running  on the machine ABC, which is different from the rlogin service
       running on the machine XYZ.  The third part of a Kerberos name  is  the
       realm.   The  realm  corresponds  to  the  Kerberos  service  providing
       authentication for the principal.

       When writing a Kerberos name, the principal name is separated from  the
       instance  (if  not  null)  by  a slash, and the realm (if not the local
       realm) follows, preceded by an ‘‘@’’ sign.  The following are  examples
       of valid Kerberos names:

               david
               jennifer/admin
               joeuser@BLEEP.COM
               cbrown/root@FUBAR.ORG

       When  you  authenticate  yourself  with  Kerberos  you  get  an initial
       Kerberos ticket.  (A Kerberos ticket is an encrypted  protocol  message
       that  provides  authentication.)  Kerberos uses this ticket for network
       utilities such as rlogin and rcp.  The  ticket  transactions  are  done
       transparently, so you don’t have to worry about their management.

       Note,  however, that tickets expire.  Privileged tickets, such as those
       with the instance ‘‘root’’, expire in a few minutes, while tickets that
       carry  more ordinary privileges may be good for several hours or a day,
       depending on the installation’s policy.  If your login session  extends
       beyond  the  time  limit,  you will have to re-authenticate yourself to
       Kerberos to get new tickets.  Use the kinit command to  re-authenticate
       yourself.

       If you use the kinit command to get your tickets, make sure you use the
       kdestroy command to destroy your tickets  before  you  end  your  login
       session.   You  should put the kdestroy command in your .logout file so
       that your tickets will be destroyed automatically when you logout.  For
       more  information  about  the  kinit  and  kdestroy  commands,  see the
       kinit(1) and kdestroy(1) manual pages.

       Kerberos tickets can be forwarded.  In order to  forward  tickets,  you
       must  request  forwardable  tickets  when  you  kinit.   Once  you have
       forwardable tickets, most Kerberos programs have a command line  option
       to forward them to the remote host.

       Currently,  Kerberos  support  is  available  for the following network
       services: rlogin, rsh, rcp, telnet, ftp, krdist (a  Kerberized  version
       of rdist), ksu (a Kerberized version of su), login, and Xdm.

SEE ALSO

       kdestroy(1),   kinit(1),   klist(1),   kpasswd(1),   rsh  (1),  rcp(1),
       rlogin(1), telnet(1), ftp(1), krdist(1),  ksu(1),  sclient(1),  xdm(1),
       des_crypt(3),   hash(3),   krb5strings(3),  krb5.conf(5),  kdc.conf(5),
       kadmin(8), kadmind(8), kdb5_util(8),  telnetd(8),  ftpd(8),  rdistd(8),
       sserver(8), klogind(8c), kshd(8c), login(8c)

BUGS

AUTHORS

       Steve Miller, MIT Project Athena/Digital Equipment Corporation
       Clifford Neuman, MIT Project Athena

HISTORY

       Kerberos  was  developed  at  MIT.   OpenVision rewrote and donated the
       administration server, which is used in the current version of Kerberos
       5.

RESTRICTIONS

       Copyright    1985,1986,1989-1996,2002    Massachusetts   Institute   of
       Technology

                                                                   KERBEROS(1)