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