informational document describing the implementation phase and the
detailed coordination procedures is expected. The deployment phase
must also follow the directives produced by the current work on
RFC1327 mapping authorities, in order to insure consistency in the
mapping information itself.
Another distributed directory service which can distribute the
RFC1327 mapping information is X.500. The coordination, alignment and
uniqueness of mapping information between DNS and X.500 is an
essential fact if it happens to have both systems in place. The ideal
solution is a dynamic alignment mechanism which transparently makes
the DNS mapping information available in X.500 and vice versa. Some
work in this specific field is already being done [see Costa] which
can result in a global transparent directory service, where the
information is stored in DNS or in X.500, but is visible completely
by any of the two systems.
7. Conclusion
The introduction of the new PX resource record and the definition of
the X.400 O/R name space in the DNS structure provide a good
repository for mapping information. The mapping information is stored
in the DNS tree structure so that it can be easily obtained using the
DNS distributed name service. At the same time the definition of the
appropriate DNS space for X.400 O/R names provide a repository where
to store and distribute some other X.400 MHS information. The use of
the DNS has many known advantages in storing, managing and updating
the information. A successful number of tests have been performed
under the provisional top level domain "X400.IT", and their results
confirmed the advantages of the method.
Software to query the DNS and then to convert between the textual
representation of DNS resource records and the address format defined
in RFC1327 needs to be developed. This software must also allow a
smooth implementation and deployment period, eventually taking care
of the transition phase. A further informational document describing
operational and implementation of the service is expected.
8. Acknowledgements
We wish to thanks all those who contributed to the discussion and
revision of this document: many of their ideas and suggestions
constitute essential parts of this work. In particular thanks to Jon
Postel, Paul Mockapetris, Rob Austin and the whole IETF x400ops, RARE
wg-msg and IETF namedroppers groups. A special mention to Christian
Huitema for his fundamental contribution to this work.
9. References
[CCITT] CCITT SG 5/VII, "Recommendation X.400, Message Handling
Systems: System Model - Service Elements", October 1988.
[RFC1327] Kille, S., "Mapping between X.400(1988)/ISO 10021 and RFC
822", RFC1327, March 1992.
[RFC1034] Mockapetris, P., "Domain Names - Concepts and Facilities",
STD 13, RFC1034, USC/Information Sciences Institute, November
1987.
[RFC1035] Mockapetris, P., "Domain names - Implementation and
Specification", STD 13, RFC1035, USC/Information Sciences
Institute, November 1987.
[RFC1033] Lottor, M., "Domain Administrators Operation Guide", RFC
1033, SRI International, November 1987.
[Costa] Costa, A., Macedo, J., and V. Freitas, "Accessing and
Managing DNS Information in the X.500 Directory", Proceeding of
the 4th Joint European Networking Conference, Trondheim, NO, May
1993.
[Houttin] Houttin, J., Hansen, K., and S. Aumont, "Address Mapping
Functions and Authorities", Internet-DRAFT, May 1993.
10. Security Considerations
Security issues are not discussed in this memo.
11. Authors' Addresses
Claudio Allocchio
Sincrotrone Trieste
Padriciano 99
I 34012 Trieste
Italy
RFC822: Claudio.Allocchio@elettra.trieste.it
X.400: C=it;A=garr;P=Trieste;O=Elettra;
S=Allocchio;G=Claudio;
Phone: +39 40 3758523
Fax: +39 40 226338
Antonio Blasco Bonito
CNUCE - CNR
Reparto infr. reti
Viale S. Maria 36
I 56126 Pisa
Italy
RFC822: bonito@cnuce.cnr.it
X.400: C=it;A=garr;P=cnr;O=cnuce;S=bonito;
Phone: +39 50 593246
Fax: +39 50 589354
Bruce Cole
Cisco Systems Inc.
P.O. Box 3075
1525 O'Brien Drive
Menlo Park, CA 94026
U.S.A.
RFC822: bcole@cisco.com
X.400: C=us;A= ;P=Internet;
DD.rfc-822=bcole(a)cisco.com;
Phone: +1 415 6888245
Fax: +1 415 6884575
Silvia Giordano
Centro Svizzero di
Calcolo Scientifico
Via Cantonale
CH 6928 Manno
Switzerland
RFC822: giordano@cscs.ch
X.400: C=ch;A=arcom;P=switch;O=cscs;
S=giordano;
Phone: +41 91 508213
Fax: +41 91 506711
Robert Hagens
Advanced Network and Services
1875 Campus Commons Drive
Reston, VA 22091
U.S.A.
RFC822: hagens@ans.net
X.400: C=us;A= ;P=Internet;
DD.rfc-822=hagens(a)ans.net;
Phone: +1 703 7587700