Kerberos Principal Name Canonicalization and Cross-Realm Referrals
RFC 6806

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 13
• 14
• 15

Internet Engineering Task Force (IETF)                   S. Hartman, Ed.
Request for Comments: 6806                             Painless Security
Updates: 4120                                                 K. Raeburn
Category: Standards Track                                            MIT
ISSN: 2070-1721                                                   L. Zhu
                                                   Microsoft Corporation
                                                           November 2012

   Kerberos Principal Name Canonicalization and Cross-Realm Referrals

Abstract

   This memo documents a method for a Kerberos Key Distribution Center
   (KDC) to respond to client requests for Kerberos tickets when the
   client does not have detailed configuration information on the realms
   of users or services.  The KDC will handle requests for principals in
   other realms by returning either a referral error or a cross-realm
   Ticket-Granting Ticket (TGT) to another realm on the referral path.
   The clients will use this referral information to reach the realm of
   the target principal and then receive the ticket.  This memo also
   provides a mechanism for verifying that a request has not been
   tampered with in transit.  This memo updates RFC 4120.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6806.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect

Hartman, et al.              Standards Track                    [Page 1]
RFC 6806                      KDC Referrals                November 2012

   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Conventions Used in This Document  . . . . . . . . . . . . . .  4
   3.  Requesting a Referral  . . . . . . . . . . . . . . . . . . . .  4
   4.  Realm Organization Model . . . . . . . . . . . . . . . . . . .  5
     4.1.  Trust Assumptions  . . . . . . . . . . . . . . . . . . . .  5
   5.  Enterprise Principal Name Type . . . . . . . . . . . . . . . .  6
   6.  Name Canonicalization  . . . . . . . . . . . . . . . . . . . .  7
   7.  Client Referrals . . . . . . . . . . . . . . . . . . . . . . .  9
   8.  Server Referrals . . . . . . . . . . . . . . . . . . . . . . . 10
   9.  Cross-Realm Routing  . . . . . . . . . . . . . . . . . . . . . 11
   10. Caching Information  . . . . . . . . . . . . . . . . . . . . . 11
   11. Negotiation of FAST and Detecting Modified Requests  . . . . . 12
   12. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13
   13. Security Considerations  . . . . . . . . . . . . . . . . . . . 13
     13.1. Shared-Password Case . . . . . . . . . . . . . . . . . . . 16
     13.2. Pre-Authentication Data  . . . . . . . . . . . . . . . . . 16
   14. Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 17
   15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
     15.1. Normative References . . . . . . . . . . . . . . . . . . . 17
     15.2. Informative References . . . . . . . . . . . . . . . . . . 17
   Appendix A.  Compatibility with Earlier Implementations of
                Name Canonicalization . . . . . . . . . . . . . . . . 18