Document OPS-9 (Postmaster Convention for X.400 Operations)

[Allan Cargille <[e-mail]>]

Hi, here's my draft document on support for postmaster addresses in
X.400 domains for which RFC1327 mapping rules are defined.

Alf referred to this document as OPS-9 in the agenda and the filestore
for the upcoming IETF meeting in Washington, DC.

We'll discuss this at the IETF meeting, but comments are encouraged
from other people as well.

I have also submitted this document as an Internet Draft, so it should
be appearing shortly.

Cheers,

allan

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          INTERNET DRAFT                                      Nov 1992


                   Postmaster Convention for X.400 Operations

                          Sat Nov 14 21:58:15 CST 1992


                               C. Allan Cargille
                            University of Wisconsin
                           [e-mail]





          This draft document is being circulated for comment.

          If consensus is reached it may be submitted to the RFC
          editor as a Proposed Standard protocol specification, for
          use in X.400 in the Internet.

          Please send comments to the author, or to the IETF OSI X.400
          Operations Working Group mailing list
          <[e-mail]>.

          The following text is required by the Internet-draft rules:

              This document is an Internet Draft.  Internet Drafts
              are working documents of the Internet Engineering
              Task Force (IETF), its Areas, and its Working
              Groups. Note that other groups may also distribute
              working documents as Internet Drafts.

              Internet Drafts are draft documents valid for a
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              than as a "working draft" or "work in progress."

              Please check the I-D abstract listing contained in
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          Abstract:

               Both RFC822 and 1173 (Host Requirements) require that
               the email address "postmaster" be supported at all
               hosts.  This paper extends this concept to X.400 mail
               domains which have registered RFC1327 mapping rules
               (and therefore which appear to have normal RFC822-style
               addresses).





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          1.  Postmaster Convention in RFC822

          Operating a reliable, large-scale electronic mail (email)
          network requires cooperation between many mail managers and
          system administrators.  As noted in RFC822 [1], often mail
          or system managers need to be able to contact a responsible
          person at a remote host without knowing any specific user
          name or address at that host.  For that reason, both RFC822
          and the Internet Host Requirements [2] require that the
          address "postmaster" be supported at every Internet host.

          2.  Postmaster Convention and X.400

          However, RFC822 is not the only email protocol being used in
          the Internet.  Some Internet sites are also running the
          X.400 (1984) email protocol [3].  In the near future, the
          1988 X.400 protocol is also expected to be in use [4].
          RFC1327 specifies how to map between X.400 and RFC822
          addresses [5].  When mapping rules are used, addresses map
          cleanly between X.400 and RFC822.  In fact, it is impossible
          to determine by inspecting the address whether the recipient
          is an RFC822 mail user or an X.400 mail user.

          A paper by Rob Hagens and Alf Hansen describes an X.400
          community known as the "Global Open MHS Community" (GO-MHS)
          [6].  Many mail domains in the GO-MHS Community have
          registered RFC1327 mapping rules.  Therefore, users in those
          domains have RFC822-style email addresses, and these email
          domains are a logical extension of the RFC822 Internet.  It
          is impossible to tell by inspecting a user's address whether
          the user receives RFC822 mail or X.400 mail.

          Since these addresses appear to be standard RFC822
          addresses, mail managers, mailing list managers, host
          administrators, and users expect to be able to simply send
          mail to "postmaster@domain" and having the message be
          delivered to a responsible party.  When an RFC1327 mapping
          rule exists, the X.400 address elements corresponding to the
          left-hand-side "postmaster" are "Surname=Postmaster" (both
          1984 and 1988) and "CommonName=Postmaster" (1988 only).
          However, neither the X.400 protocols, North America X.400
          Implementor's Agreements [7], nor the European X.400
          Implementor's Agreements [8] require that
          "Surname=Postmaster" and "CommonName=Postmaster" be
          supported.  (Supporting these addresses is recommended in
          X.400 (1988)).

          For mapped X.400 domains which do not support the postmaster
          address(es), this means that an address such as
          "[e-mail]" might be valid, yet mail to the
          corresponding address "[e-mail]" fails.
          This is frustrating for remote administrators and users, and
          can even prevent operational problems from being


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          DRAFT           X.400 Postmaster Convention         Nov 1992


          communicated and resolved.  In this case, the desired
          seamless integration of the Internet RFC822 mail world and
          the mapped X.400 domain has not been achieved.

          The X.400 mail managers participating in the Cosine MHS
          Project discussed this problem in a meeting in June 1992
          [9].  The discussion recognized the need for supporting the
          postmaster address at any level of the address hierarchy
          where these are user addresses.  However, in the end, the
          Cosine MHS Managers only recommended support of the
          postmaster address Surname and Common Name at all levels of
          the address hierarchy down to the Organization level--that
          is, only for addresses of the form

              C=xx; ADMD=someadmd; S=postmaster
              C=xx; ADMD=someadmd; O=org; S=postmaster
              C=xx; ADMD=someadmd; PRMD=someprmd; S=postmaster
              C=xx; ADMD=someadmd; PRMD=someprmd; O=org; S=postmaster


          While there is value in supporting postmaster addresses down
          to the Organization level, this does not solve the entire
          problem of consistent email management between the Internet
          RFC822 world and mapped X.400 mail domains.  Specifically,
          there are cases where a user's RFC822-style address maps
          into an X.400 address containing attributes below
          Organization, such as Organizational Units.  Again, RFC822
          community members have no idea what the X.400 representation
          of the address is, nor should they need to know.  However,
          they expect that if they can send mail to (for example)
          "[e-mail]", then they should also be able to mail
          "[e-mail]".  If they cannot, then the
          desired seamless integration of the X.400 and RFC822 mail
          worlds has not been realized, and the quality of service has
          broken down.

          3.  Proposed Solution

          To fully achieve the desired seamless integration of email
          domains for which RFC1327 mapping rules have been defined,
          the following convention must be followed,

              If there are any valid addresses of the form
              "user@domain", then the address "postmaster@domain"
              must also be valid.

          To express this in terms of X.400:  For every X.400 domain
          for which an RFC1327 mapping rule exists, if any address of
          the form

              Surname=User; <Other X.400 Address Elements>

          is a valid address, then the address


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          DRAFT           X.400 Postmaster Convention         Nov 1992


              Surname=Postmaster; <Same X.400 Address Elements>

          must also be a valid address.  If the X.400 system is
          running X.400(1988), then the address

              CommonName=Postmaster; <Same X.400 Address Elements>

          must also be supported.

          To remain consistent with RFC822, "Mail sent to that address
          is to be routed to a person responsible for the site's mail
          system or to a person with responsibility for general site
          operation." [10]

          4.  References

          [1]  RFC822

          [2]  RFC1173

          [3]  X.400 (1984)

          [4]  X.400 (1988)

          [5]  RFC1327

          [6]  presently draft-ietf-x400ops-mgtdomains-ops-02.txt

          [7]  NIST X.400 Implementors Agreements

          [8]  EWOS X.400 Implementors Agreements

          [9]  Minutes from June 1992 Cosine MHS Managers Meeting

          [10] RFC822, direct quote




















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