Using the Internet DNS to Distribute RFC1327 Mail Address Mapping Tables
RFC 1664
| Document | Type |
RFC - Experimental
(August 1994; No errata)
Obsoleted by RFC 2163
|
|
|---|---|---|---|
| Last updated | 2013-03-02 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 1664 (Experimental) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | (None) | ||
| Send notices to | (None) | ||
Network Working Group C. Allocchio
Request for Comments: 1664 A. Bonito
Category: Experimental GARR-Italy
B. Cole
Cisco Systems Inc.
S. Giordano
Centro Svizzero Calcolo Scientifico
R. Hagens
Advanced Network & Services
August 1994
Using the Internet DNS to Distribute
RFC1327 Mail Address Mapping Tables
Status of this Memo
This memo defines an Experimental Protocol for the Internet
community. This memo does not specify an Internet standard of any
kind. Distribution of this memo is unlimited.
Abstract
This memo defines how to store in the Internet Domain Name System the
mapping information needed by e-mail gateways and other tools to map
RFC822 domain names into X.400 O/R names and vice versa. Mapping
information can be managed in a distributed rather than a centralised
way. Gateways located on Internet hosts can retrieve the mapping
information querying the DNS instead of having fixed tables which
need to be centrally updated and distributed. This memo is a joint
effort of X400 operation working group (x400ops) and RARE Mail and
Messaging working group (WG-MSG).
1. Introduction
The connectivity between the Internet SMTP mail and other mail
services, including the Internet X.400 mail and the commercial X.400
service providers, is assured by the Mail eXchanger (MX) record
information distributed via the Internet Domain Name System (DNS). A
number of documents then specify in details how to convert or encode
addresses from/to RFC822 style to the other mail system syntax.
However, only conversion methods provide, via some algorithm or a set
of mapping rules, a smooth translation, resulting in addresses
indistinguishable from the native ones in both RFC822 and foreign
world.
RFC1327 describes a set of mappings which will enable interworking
between systems operating the CCITT X.400 (1984/88) Recommendations
Allocchio, Bonito, Cole, Giordano & Hagens [Page 1]
RFC 1664 Internet DNS for Mail Mapping Tables August 1994
and systems using the RFC822 mail protocol, or protocols derived from
RFC822. That document addresses conversion of services, addresses,
message envelopes, and message bodies between the two mail systems.
This document is concerned with one aspect of RFC1327: the mechanism
for mapping between X.400 O/R addresses and RFC822 domain names. As
described in Appendix F of RFC1327, implementation of the mappings
requires a database which maps between X.400 O/R addresses and domain
names, and this database is statically defined.
This approach requires many efforts to maintain the correct mapping:
all the gateways need to get coherent tables to apply the same
mappings, the conversion tables must be distributed among all the
operational gateways, and also every update needs to be distributed.
This static mechanism requires quite a long time to be spent
modifying and distributing the information, putting heavy constraints
on the time schedule of every update. In fact it does not appear
efficient compared to the Internet Domain Name Service (DNS). More
over it does not look feasible to distribute the database to a large
number of other useful applications, like local address converters,
e-mail User Agents or any other tool requiring the mapping rules to
produce correct results.
A first proposal to use the Internet DNS to store, retrieve and
maintain those mappings was introduced by two of the authors (B. Cole
and R. Hagens) adopting two new DNS resource record (RR) types: TO-
X400 and TO-822. This new proposal adopts a more complete strategy,
and requires one new RR only. The distribution of the RFC1327 mapping
rules via DNS is in fact an important service for the whole Internet
community: it completes the information given by MX resource record
and it allows to produce clean addresses when messages are exchanged
among the Internet RFC822 world and the X.400 one (both Internet and
Public X.400 service providers).
A first experiment in using the DNS without expanding the current set
of RR and using available ones was in the mean time deployed by some
of the authors. The existing PTR resource records were used to store
the mapping rules, and a new DNS tree was created under the ".it" top
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