KERBEROS(1)                                                                                                          KERBEROS(1)



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  with-
       out  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, how-
       ever, 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 ser-
       vice 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
               joeuserATBLEEP.COM
               cbrown/rootATFUBAR.ORG

       When you authenticate yourself with Kerberos you get an initial Kerberos ticket.  (A Kerberos ticket is an encrypted pro-
       tocol  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  min-
       utes,  while tickets that carry more ordinary privileges may be good for several hours or a day, depending on the instal-
       lation's policy.  If your login session extends beyond the time limit, you will have to re-authenticate yourself to  Ker-
       beros 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



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