home *** CD-ROM | disk | FTP | other *** search
-
- CURRENT_MEETING_REPORT_
-
- Reported by C. Allan Cargille/MCI
-
- Minutes of the Mail Extensions Working Group (MAILEXT)
-
-
- Agenda
-
- o Introduction, participants, approval of minutes, revise charter,
- revise agenda.
-
- o Individual work items:
- - 521 status codes proposal (John Myers).
- - Language tag proposal (Harald Alvestrand).
- - File transfer body part MIME mapping (Ned Freed).
- - Pipelining SMTP extension (Ned Freed).
- - Checkpointing SMTP extension (Dave Crocker and Ned Freed).
- - Binary and chunking SMTP extensions (Greg Vaudreuil).
- - A-BoMBS and C-BoMBS (Jerome Houttein).
- - Text/html proposal from the HTML working group (Eric Huizer
- presenting).
-
-
- Jacob Palme asked if this group is an appropriate forum for discussion
- of work being done in the X.400/OSI community on incorporation of
- Internet addressing. John Klensin responded that this is not an
- appropriate forum for such discussion, but that it can be discussed if
- time permits.
-
-
- 521 Status Codes Proposal
-
- John Myers presented an overview of the 521 status code proposal. In
- brief, this proposal is something that network entities that do not
- support e-mail would support. It causes mail to immediately bounce when
- an attempt is made to send it to such an entity. Currently such mail
- tends to sit in some queue somewhere until it times out and is returned.
-
- Keith Moore raised the issue of how MX records pointing at such entities
- should work. The current specification says that the message should
- bounce. Keith argued that it would be preferable to try other MX
- records instead.
-
- John Myers then pointed out that he had recently realized that this
- proposal is not necessary. It is almost as easy to implement a simple
- SMTP parser that returns a 5xx code to any RCPT TO command. This
- approach has the advantage it works with existing broken implementations
- that effectively ignore the initial banner status.
-
- Harald Alvestrand and others countered by saying that standarding the
- meaning of 521 in this context is useful in its own right. In addition,
- John's proposal is problematic in that it could be construed that the
- postmaster address should always work.
-
- Harald also suggested that this proposal needs to be tried to be
- assessed. If it is deployed and is useful it could be moved to
- standards track. If not, it should be dropped. This in turn argues
- that the document should be issued as Experimental. Allan concluded by
- suggesting that the document authors should attempt to reach consensus
- on the list for the documents moving forward as Experimental.
-
-
- Language Tag Proposal
-
- The group considered the language header proposal. Harald summarized
- this proposal as one that allows labelling the content of a message or
- part of a message as being in a particular language.
-
- Jacob asked if the language concept extends to computer languages.
- Harald said it does not, but it could be extended to cover this.
- Nathaniel Borenstein asked about how multi-lingual text is handled -- it
- is done by specifying multiple language values.
-
- Ned Freed noted that this work may be part of future efforts in
- extending MIME to uses in non-messaging environments. This should not
- preclude moving the document along the standards track now, however.
-
- John Klensin pointed out that the syntactic use of dash differs from
- previous usage in RFC 822. Harald responded that this is by design, in
- that while the dash is a syntactic element he wants to capitalize on the
- effect it has of making it look like a single token. Dave Crocker added
- that this needed to be made explicit in the text.
-
- Dave Crocker also raised the issue of why this does not make sense as a
- content-type parameter. Ned countered by pointing out that global
- content type parameters are not allowed in MIME, and that this
- information spans multiple content types.
-
- The group concluded that this document should be submitted for
- consideration by the IESG as a Proposed Standard.
-
-
- File Transfer Body Part MIME Mapping
-
- Ned presented his file transfer body part, SMTP pipelining, and SMTP
- checkpointing extension. Ned prefaced his remarks by stating that only
- the pipelining extension is a candidate for advancement at this time.
-
- The file transfer body part work is a result of work undertaken by the
- EMA Message Attachment Working Group (MAWG). The specification seeks to
- map X.400 file transfer body parts into appropriate MIME objects and
- vice versa.
-
- Discussion focused on the need for a general file transfer mechanism in
- MIME and whether or not this mechanism should be extended to provide
- this facility. Ned pointed out that since the EMA's use of file
- transfer body part is to provide a MIME-like mechanism for object
- encapsulation, not to use the mechanism for the (obvious) purpose to
- transfer files per se, and as such the mapping specification seeks to
- provide an object mapping rather than a file transfer mechanism.
-
- Eric Fair noted that in the best of all worlds it would be possible to
- specify generic formats for generic object types. Dave Crocker and
- others noted that while this would be desirable it is not present-day
- reality, and is not likely to become reality in the foreseeable future.
-
- The discussion concluded with Ned stating that he wants to consider the
- various issues brought up by the group and see how the document needs to
- be changed (or not changed) to accommodate them.
-
-
-
- Pipelining SMTP Extension
-
- Ned reported that, as tasked by the working group, he had communicated
- with Eric Allman about the issues of implementing the pipelining
- extension in sendmail. Eric had responded that the problems with
- implementing pipelining in sendmail (e.g., the use of a fork system
- calls in the middle of the SMTP dialogue) would probably be addressed in
- the long term by other planned modifications. As such, Ned recommended
- moving the document forward for consideration as a Proposed Standard
- without any sendmail-specific changes, and the working group agreed.
-
-
-
- Checkpointing SMTP Extension
-
- The checkpointing proposal was discussed. One of the coauthors (Ned)
- had thought of this proposal as something of an academic exercise.
- However, the other author (Dave Crocker) disagreed and so did a
- considerable fraction of the group. It was accordingly decided that
- implementation of this proposal is needed, and if it proves to be useful
- the working group should consider moving this work forward on a
- standards track.
-
-
-
- Binary and Chunking SMTP Extensions
-
- Greg Vaudreuil presented his chunking and binary SMTP extension
- specification. Discussion centered on interoperability testing and
- issues surrounding binary MIME. The latter were ruled out of scope for
- the present discussion, but the former are of such concern that the
- working group decided to ask for some indication of interoperability
- before advancing the document to Proposed Standard.
-
-
- A-BoMBS and C-BoMBS
-
- The BoMBS documents were reviewed. A large number of substantive
- comments were made about both documents. Dave Crocker stated that this
- work is extremely important and long overdue, and that the best approach
- would be to charter a separate working group to deal with these
- documents in detail. This suggestion was favorably received by the
- working group.
-
-
- Text/html Proposal from the HTML Working Group
-
- Eric Huizer presented a proposal for the handling of text/html, which
- was worked out by the HTML Working Group (which met in parallel with
- Mail Extensions Working Group). In brief, the HTML group has decided on
- a canonical form that agrees with MIME text/plain (i.e CRLF line
- terminator sequence). Clients are supposed to support a wider variety
- of terminators, but text/html is supposed to be in this form. This
- proposal was very favorably received by the Mail Extensions Working
- Group.
-
- Eric Huizer also presented a proposal for a MIME testing service. A
- document will be posted to the list describing this service.
-
-
- Conclusion
-
- Allan Cargille concluded the meeting by thanking the various document
- authors for the work they have done on these proposals.
-
-