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-
- CURRENT_MEETING_REPORT_
-
- Reported by Keith Moore/University of Tennessee
-
- Minutes of the Detailed Revision/Update of Message Standards Working
- Group (DRUMS)
-
- These minutes are based on notes taken by Rodney Tillotson.
-
- Since this was the first meeting of the working group and there were no
- drafts of the revised mail standards available by the Internet-Drafts
- deadline, the chair proposed that the meeting time be used to discuss a
- small number of contentious issues, in the hope that the face-to-face
- contact would facilitate reaching closure on one or more of them.
-
- The chair therefore produced a list of issues gleaned from discussions
- on the mailing list, and took suggestions from the floor for additional
- issues worthy of discussion.
-
-
- Issues Proposed for Discussion
-
- The issues proposed for discussion were:
-
- Syntax changes:
-
-
- 1. Mark Crispin's proposal (from the mailing list) that we remove
- ``['', ``]'' and ``.'' from ``specials'' and redefine
- ``local-part'' and ``domain'' to be just ``word''. (Discussed
- below.)
-
- 2. How should IPv6 domain literals be represented?
-
- 3. Should we unify 821 and 822 address syntax, and if so, what should
- the grammar be? (Subsumed by 21.)
-
-
- Others:
-
-
- 4. Discuss use of SMTP as a message submission protocol (what to do
- about missing headers, etc.).
-
- 5. Discuss use of RFC 822 as a message submission protocol (how to
- handle Bcc: etc.).
-
- 6. What do/should the Resent-* headers really mean?
-
- 7. Should we restrict the names or kinds of user-defined message
- headers? For example:
-
- a. Forbid field-names Content-* unless they are part of MIME.
-
- b. Forbid fields that are supposed to be interpreted by MTAs
- (during transport or delivery).
-
- 8. Interaction of headers with mailing lists? (Subsumed by 10.)
-
-
- Harald Alvestrand's (paraphrased) additions, also circulated beforehand:
-
-
- 9. Headers: should we require registration of non-``X-'' headers?
- (reactivating a sleeping clause in RFC 822).
-
- 10. Should we define the behavior of mailing lists?
-
- 11. What tack should we take on syntax changes?
-
- - No changes whatsoever?
- - Should we only make the syntax stricter than 822?
- - Should we loosen the 822 syntax, perhaps with warnings?
- - Be liberal (822-compliant) in what you receive, be conservative
- (DRUMS-compliant) in what you send?
-
- 12. Can we invent a name for the message format (other than
- ``RFC822''), or should we call it ``Internet Mail''?
-
-
- Added in the meeting:
-
-
- 13. What is the meaning of Usenet headers in e-mail.
-
- 14. Ambiguity about Reply-To: (both the UA action and the field
- specification).
-
- 15. Places where RFC 822 specifies syntax but no semantics.
-
- 16. HTTP headers which clash with mail ones (this was declared out of
- scope for the DRUMS Working Group).
-
- 17. What does ``authoritative'' mean in RFC 822?
-
- 18. Received-*: headers: what is the syntax and what can you do with
- them?
-
- 19. What are the guiding principles for the bouncing of mail? (NOTARY
- fixes a few things.)
-
- 20. The UA-MTA model: what is a reflector? an exploder? Should we
- devise a taxonomy of several meanings?
-
- 21. RFC 821 and RFC 822 together: remove obsolete parts and harmonize
- syntax specifications.
-
- 22. Should we revisit the RFC 822 rule requiring at least one To, Cc,
- or Bcc: address?
-
- 23. RFC 822 does not clearly specify the use of msg-id in replies (it
- provides two syntaxes, but ``unique'' is not specified).
-
- 24. What categories of alteration to a message justify changing or
- preserving the msg-id?
-
-
- Einar Stefferud also expressed interest in producing a document
- describing an MTA-UA model for Internet mail. The chair suggested that
- this not be discussed at the meeting itself, but instead that he and
- other interested working group members collaborate on a draft or outline
- of such a document, and submit it to the group for consideration as to
- whether the group should produce such a document as an RFC.
-
- The chair attempted to reduce the above list to a shorter list which
- could be discussed at the meeting. The most attractive possibility was
- to dispose promptly of items which allowed it, but after several
- cautious attempts it appeared that at the time there were no issues
- which this meeting could deal with in this way. Several of them raised
- more general questions about the approach to take and the amount of
- damage which could be inflicted on the existing standards or the
- existing user and product base, and it was hoped that detailed
- discussion of one or more specific issues.
-
- The short list was reduced to about three items, although the first item
- in that short list (Mark Crispin's proposal) consumed almost all the
- remaining time.
-
-
- Discussion
-
- Mark Crispin's proposal (1 above) was that we remove ``['', ``]'' and
- ``.'' from specials and redefine local-part and domain to be just
- ``word''. This would (among other things) allow ``.''s in phrases. On
- the one hand, this would make life simpler for parsers; on the other, it
- might encourage generation of even more messages that aren't compatible
- with existing mailers.
-
- The intended effect of such a change is to remove the requirement to
- quote name phrases containing the above characters, which are currently
- ``specials'' as defined by RFC 822. From an end user point of view, it
- would be worth some additional parsing effort to remove what may seem an
- arbitrary restriction. In most cases where the quoting requirement is
- not honored, a human reader can immediately tell what is intended as in,
- for example:
-
-
- To: A.Random User <aru@somewhere>
-
-
- However, RFC 822 assumes that lexical analysis of addresses is not
- context dependent so that the name phrase receives the same treatment as
- an address. Simply removing ``.'' from specials would allow some
- addresses which are currently invalid, such as:
-
-
- <...hi.there...@cs.utk.edu>
-
-
- An alternative suggestion was that the RFC 822 grammar should not be
- changed, but that advice could be generated on parsing incoming
- addresses which are out of specification.
-
- Discussion spread to compare the cost of making changes in general with
- the cost of not making them. It was pointed out that the earlier
- transition from RFC 733 to RFC 822 working was justified because it had
- by then become essential (even though it was expected to cause at least
- some failures); but also that the community affected by intrusive
- changes now is orders of magnitude greater than it was then.
-
- Where practice has diverged from standards, normally the standards
- should be updated or the practices banned. Rules should only be relaxed
- where there are compelling reasons.
-
- It should be remembered that RFC 822 (for instance) is referred to by
- many other RFCs and other documents, and that changes to it even when
- considered necessary might have effects which cannot easily be foreseen.
-
- The chair pointed out that it was necessary to consider the resulting
- effect on user agents that would have to maintain backward compatibility
- with existing user agents. A change intended as a simplification might
- in reality make implementation more complicated, reduce interoperability
- with the installed base, or make it more difficult to understand what is
- required to produce a user agent that is interoperable in practice.
- Even after the change took effect, an effective user agent would still
- have to support both the old and the new versions of the message format.
-
- Dave Crocker proposed several categories of change:
-
-
- o Specifications which are broken.
- o Specifications which are unclear.
- o Limitations now considered inappropriate.
- o Enhancements.
-
-
- It is also desirable to simplify the specifications where possible.
-
- Criteria against which to assess the value of a proposed change are:
-
-
- o Simplicity of the resulting specification.
- o Benefits to users of changes proposed.
- o Impact on the installed base.
-
-
- Dave Crocker agreed to write a draft describing this taxonomy for
- circulation to working group members.
-
- The allotted time having elapsed for the meeting, the chair suggested
- that the above discussion be continued on the mailing list, and the
- meeting was adjourned.
-
-