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32 .\" $Heimdal: kerberos.8 16121 2005-10-03 14:24:36Z lha $
40 .Nd introduction to the Kerberos system
42 Kerberos is a network authentication system. Its purpose is to
43 securely authenticate users and services in an insecure network
46 This is done with a Kerberos server acting as a trusted third party,
47 keeping a database with secret keys for all users and services
51 Each principal belongs to exactly one
53 which is the administrative domain in Kerberos. A realm usually
54 corresponds to an organisation, and the realm should normally be
55 derived from that organisation's domain name. A realm is served by one
56 or more Kerberos servers.
58 The authentication process involves exchange of
62 which together prove the principal's identity.
64 When you login to the Kerberos system, either through the normal
65 system login or with the
67 program, you acquire a
68 .Em ticket granting ticket
69 which allows you to get new tickets for other services, such as
73 without giving your password.
75 For more information on how Kerberos works, and other general Kerberos
76 questions see the Kerberos FAQ at
77 .Pa http://www.nrl.navy.mil/CCS/people/kenh/kerberos-faq.html .
79 For setup instructions see the Heimdal Texinfo manual.
88 The Kerberos authentication system was developed in the late 1980's as
89 part of the Athena Project at the Massachusetts Institute of
90 Technology. Versions one through three never reached outside MIT, but
91 version 4 was (and still is) quite popular, especially in the academic
92 community, but is also used in commercial products like the AFS
95 The problems with version 4 are that it has many limitations, the code
96 was not too well written (since it had been developed over a long
97 time), and it has a number of known security problems. To resolve many
98 of these issues work on version five started, and resulted in IETF RFC
99 1510 in 1993. IETF RFC 1510 was obsoleted in 2005 with IETF RFC 4120,
100 also known as Kerberos clarifications. With the arrival of IETF RFC
101 4120, the work on adding extensibility and internationalization have
102 started (Kerberos extensions), and a new RFC will hopefully appear
105 This manual page is part of the
107 Kerberos 5 distribution, which has been in development at the Royal
108 Institute of Technology in Stockholm, Sweden, since about 1997.