Final postmaster document -- please proofread

[Allan Cargille <[e-mail]>]

Hello x400ops folk,

Here is the long-awaited revised postmaster document.  I still need
information for the reference to the EWOS documents, but otherwise it
should be in final form.  Please proofread the document if you can
make the time.  I will accept comments at the IETF in person or until the
following Monday, April 4th via email, and then we will work to have
the document submitted as an RFC.

Thanks, everyone, for your help!  See you soon,

allan

PS - Internet Drafts - please install this as
     draft-ietf-x400ops-postmaster-04.txt.  Thanks.

=============== snip snip ============================================







      draft-ietf-x400ops-postmaster-04.txt        x400ops Working Group
      INTERNET DRAFT                                         March 1994



		 Postmaster Convention for X.400 Operations

			Thu Mar 24 18:09:56 CST 1994


			      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]>.

      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 maximum of six
      months.  Internet Drafts may be updated, replaced, or obsoleted
      by other documents at any time.  It is not appropriate to use
      Internet Drafts as reference material or to cite them other than
      as a "working draft" or "work in progress."

      Please check the I-D abstract listing contained in each Internet
      Draft directory to learn the current status of this or any other
      Internet Draft.

      Abstract:

	   Both RFC822 and RFC1123 (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 which therefore 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)
      [3] and X.400 (1988) [4] email protocols.  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 element corresponding to the left-hand-side
      "postmaster" is "Surname=Postmaster" (both 1984 and 1988).
      However, neither the X.400 protocols, North America X.400
      Implementor's Agreements [7a,7b], 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 prevent
      operational problems from being 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.



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      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, the group only required supporting the
      postmaster address down to certain levels of the O/R Address
      tree.  This approach solved part of the problem, but not all of
      it.  A more complete solution is required.

      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

	  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.  (Note that CommonName=Postmaster will
      not be generated by RFC1327 mappings, but it is recommended in
      the 1988 X.400 standard).

      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]

      3.1.  Software Limitations

      If software is unable to support this requirement, it should be
      upgraded.  X.400 software developers are strongly encouraged and
      requested to support forwarding mail to a centralized postmaster
      mailbox in products.

      It may be possible to support forwarding postmaster mail to a
      central mailbox in software packages which do not explicitly
      support it by applying work-around solutions.  For example, some
      packages support creating a mailing list for "postmaster" which


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      has one entry that points to the desired centralized postmaster
      mailbox.  Alternatively, it may be possible to support a
      postmaster address using the X.400 Autoforwarding feature.  The
      software package may also support rewriting the address in some
      other way.

      4.  Acknowledgements

      This document is a product of discussion and comments from the
      IETF OSI X.400 Operations working group.  Helpful input was also
      received from the European MHS Managers.  Special thanks to Marko
      Kaittola and Erik Lawaetz for good criticism and helpful
      discussion.

      5.  Author's Information

      Allan Cargille
      Associate Researcher
      Computer Sciences Department
      University of Wisconsin-Madison
      1210 West Dayton Street
      Madison, WI   53706   USA

      Internet: [e-mail]
      X.400:    S=Cargille; O=UW-Madison; OU1=cs; PRMD=xnren; ADMD= ; C=us;

      Voice [phone]
      Fax   [phone]

      6.  References

      [1]  Crocker, D., "Standard of the Format of ARPA Internet Text
	   Messages," RFC 822, UDEL, August 1982.  Email
	   [e-mail].

      [2]  Braden, R., "Requirements for Internet Hosts -- Application
	   and Support," RFC 1123, USC, October 1989.  Email
	   [e-mail].

      [3]  CCITT, "CCITT Recommendations X.400," Message Handling
	   Systems:  System Model--Service Elements, 1984.

      [4]  CCITT/ISO, "CCITT Recommendations X.400/ ISO IS 10021-1,"
	   Message Handling:  System and Service Overview , December
	   1988.

      [5]  RFC1327 Kille, S., "Mapping between X.400(1988) / ISO 10021
	   and RFC 822," RFC 1327, University College London, May 1992.
	   Email [e-mail].

      [6]  [presently draft-ietf-x400ops-mgtdomains-ops-06.txt] Hagens,
	   R. and A. Hansen, "Operational Requirements for X.400
	   Management Domains in the GO-MHS Community," RFC *xxxx*,


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	   *month* 1994.  Email [e-mail],
	   [e-mail].

      [7a] NIST OSI Implementors Workshop, X.400 Special Interest
	   Group, "Unofficial Stable and Working Text for the 1984
	   X.400 Implementation Agreements", Version 4, Edition 1,
	   December 1990.

      [7b] NIST OSI Implementors Workshop, X.400 Special Interest
	   Group, "Unofficial Stable and Working Text for the 1988
	   X.400 Implementation Agreements", Version 4, Edition 1,
	   December 1990.

      [8]  EWOS X.400 Implementors Agreements.  [I do not have a copy
	   of the documents, but have asked people for the appropriate
	   references.]

      [9]  Minutes, Cosine MHS Managers Meeting, June 1992
	   (unpublished).

      [10] RFC 822, page 33.


































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