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Re: rfc2821bis-01 Issue 18: Usability of 1yz replies, and Issue 17: multiline reply codes

2007-04-12 08:30:56

<pseudo chair hat on>

This thread is supposed to be about the wording of 1yz's description. It
has wandered way off course back to Issue 17 (different reply codes in
multiline responses).

Time to jump up a few thousand feet.

When moving a protocol from Proposed Standard to Draft Standard, one of
the things you need to do is look for, find and stamp out ambiguities in
the spec that have led to different implementations. When such an
ambiguity is found, either the offending portion of the protocol must be
removed from the spec or the wording changed to clarify things. A goal
is that an implementation of the old RFC should work the same under the
new RFC. Sometimes this requires a very conservative approach.

Issue 17, the possibility of different reply codes being used in
multiline responses and the question of which one should be believed, is
an example of such an ambiguity. Some people have taken the sentence
beginning "in many cases..." to be normative and others not. To me, the
wording of "in many cases" is equivalent to a MAY, which is also
equivalent to a MAY NOT. Given that there *are* implementations that
have chosen both interpretations, and we can't remove multiline
responses, I'm now convinced that we're going to need to take the
conservative approach.

If you wish to continue discussing Issue 17 (different reply codes in
multiline responses), please respond in that thread or at least change
the subject.

</pseudo chair hat off>

        Tony Hansen
        tony(_at_)att(_dot_)com

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