Additional Kerberos Naming Constraints
RFC 6111

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Internet Engineering Task Force (IETF)                            L. Zhu
Request for Comments: 6111                         Microsoft Corporation
Updates: 4120                                                 April 2011
Category: Standards Track
ISSN: 2070-1721

                 Additional Kerberos Naming Constraints

Abstract

   This document defines new naming constraints for well-known Kerberos
   principal names and well-known Kerberos realm names.

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/rfc6111.

Copyright Notice

   Copyright (c) 2011 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
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   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.

Zhu                          Standards Track                    [Page 1]
RFC 6111                     Kerberos Naming                  April 2011

   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 ....................................................2
   2. Conventions Used in This Document ...............................3
   3. Definitions .....................................................3
      3.1. Well-Known Kerberos Principal Names ........................3
      3.2. Well-Known Kerberos Realm Names ............................4
   4. Security Considerations .........................................5
   5. Acknowledgements ................................................6
   6. IANA Considerations .............................................6
   7. References ......................................................6
      7.1. Normative References .......................................6
      7.2. Informative References .....................................6

1.  Introduction

   Occasionally, protocol designers need to designate a Kerberos
   principal name or a Kerberos realm name to have a special meaning
   other than identifying a particular instance.  An example is that the
   anonymous principal name and the anonymous realm name are defined for
   the Kerberos anonymity support [RFC6112].  This anonymity name pair
   conveys no more meaning than that the client's identity is not
   disclosed.  In the case of the anonymity support, it is critical that
   deployed Kerberos implementations that do not support anonymity fail
   the authentication if the anonymity name pair is used; therefore, no
   access is granted accidentally to a principal who's name happens to
   match with that of the anonymous identity.

   However, Kerberos, as defined in [RFC4120], does not have such
   reserved names.  As such, protocol designers have resolved to use
   names that are exceedingly unlikely to have been used to avoid
   collision.  Even if a registry were set up to avoid collision of new
   implementations, there is no guarantee for deployed implementations
   preventing accidental reuse of names that can lead to access being
   granted unexpectedly.

Zhu                          Standards Track                    [Page 2]
RFC 6111                     Kerberos Naming                  April 2011

   The Kerberos realm name in [RFC4120] has a reserved name space
   although no specific name is defined and the criticality of unknown
   reserved realm names is not specified.

   This document remedies these issues by defining well-known Kerberos