NETWORK WORKING GROUP                                        N. Williams
Internet-Draft                                                       Sun
Expires: July 27, 2008                                  January 24, 2008


   GSS-API Domain-Based Service Names Mapping for the Kerberos V GSS
                               Mechanism
        draft-ietf-kitten-krb5-gssapi-domain-based-names-05.txt

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Copyright Notice

   Copyright (C) The IETF Trust (2008).

Abstract

   This document describes the mapping of GSS-API domainname-based
   service principal names onto Kerberos V principal names.









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Table of Contents

   1.  Conventions used in this document . . . . . . . . . . . . . . . 3
   2.  Domain-Based Names for the Kerberos V GSS-API Mechanism . . . . 3
   3.  Internationalization considerations . . . . . . . . . . . . . . 3
   4.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   6.  Normative References  . . . . . . . . . . . . . . . . . . . . . 4
       Author's Address  . . . . . . . . . . . . . . . . . . . . . . . 5
       Intellectual Property and Copyright Statements  . . . . . . . . 6









































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.  Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].


.  Domain-Based Names for the Kerberos V GSS-API Mechanism

   In accordance with [I-D.ietf-kitten-gssapi-domain-based-names] this
   document provides the mechanism-specific details needed to implement
   GSS-API [RFC2743] domain-based service names with the Kerberos V GSS-
   API mechanism [RFC4121].

   GSS_C_NT_DOMAINBASED_SERVICE name SHOULD be mapped to Kerberos V
   principal names as follows:
   o  the <service> name becomes the first (0th) component of the
      Kerberos V principal name;
   o  the <hostname> becomes the second component of the Kerberos V
      principal name;
   o  the <domain> name becomes the third component of the Kerberos V
      principal name;
   o  the realm of the resulting principal name is that which
      corresponds to the domain name, treated as a hostname.

   The same name canonicalization considerations and methods as used
   elsewhere in the Kerberos V GSS-API mechanism [RFC4121] and Kerberos
   V [RFC4120] in general apply here.

   Implementations SHOULD use a Kerberos V name-type of NT-SRV-HST-
   DOMAIN (integral value to be assigned, possibly after WGLC?) but MAY
   use NT-UNKNOWN instead.


.  Internationalization considerations

   It is unclear, at this time, how best to address internationalization
   of Kerberos V domain-based principal names.  This is because the
   Kerberos V core protocol internationalization project is incomplete.

   However, clearly the best way to interoperate when using Kerberos V
   domain-based principal names is to use ACE-encoded internationalized
   domain names [RFC3490] for the hostname and domain name slots of a
   Kerberos V domain-based principal name.  Therefore Kerberos V GSS-API
   mechanism implementations MUST do just that.


.  Examples



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   o  The domain based name, of generic form,
      "ldap@foo.example@ds1.foo.example" may map to a Kerberos V
      principal name like: "ldap/ds1.foo.example/
      foo.example@FOO.EXAMPLE"
   o  The domain based name, of generic form,
      "kadmin@foo.example@kdc1.foo.example" may map to a Kerberos V
      principal name like: "kadmin/kdc1.foo.example/
      foo.example@FOO.EXAMPLE"


.  Security Considerations

   See [I-D.ietf-kitten-gssapi-domain-based-names].

   It is important for the security of protocols using the Kerberos V
   GSS-API mechanism and domain-based names, that the realm of domain-
   based principal names be derived from the hostname, rather than the
   domain name slots of the input domain-based name string.


.  Normative References

   [I-D.ietf-kitten-gssapi-domain-based-names]
              Williams, N. and A. Melnikov, "GSS-API
              Internationalization and Domain-Based Service Names and
              Name Type", draft-ietf-kitten-gssapi-domain-based-names-05
              (work in progress), December 2007.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2743]  Linn, J., "Generic Security Service Application Program
              Interface Version 2, Update 1", RFC 2743, January 2000.

   [RFC3490]  Faltstrom, P., Hoffman, P., and A. Costello,
              "Internationalizing Domain Names in Applications (IDNA)",
              RFC 3490, March 2003.

   [RFC4120]  Neuman, C., Yu, T., Hartman, S., and K. Raeburn, "The
              Kerberos Network Authentication Service (V5)", RFC 4120,
              July 2005.

   [RFC4121]  Zhu, L., Jaganathan, K., and S. Hartman, "The Kerberos
              Version 5 Generic Security Service Application Program
              Interface (GSS-API) Mechanism: Version 2", RFC 4121,
              July 2005.





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Author's Address

   Nicolas Williams
   Sun Microsystems
   5300 Riata Trace Ct
   Austin, TX  78727
   US

   Email: Nicolas.Williams@sun.com










































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