Re: [Emailcore] Retrying delivery on post-DATA permanent error status

To a first order approximation and with allowances for writing
at that hour after an exhausting day, I think that is what I was
saying.

  john

--On Tuesday, July 26, 2022 07:50 -0700 Michael
<michael@linuxmagic.com> wrote:

> Weighing in, the wording SHOULD might be appropriate in
> context of a CLIENT, eg outbound spam filtering, your SMTP
> server returns 5xx, you should not click send again ;), you
> might have selected wrong outbound server as well. To say
> MUST, is impossible to enforce, programmatically given the
> wide range of possibilities that caused it
> 
> On Tue, 26 Jul 2022 01:15:39 -0400
> John C Klensin  wrote:
>> 
>> 
>> --On Monday, July 25, 2022 16:52 -0400 "Luis E. Muñoz"
>>  wrote:
>> 
>>> 
>>> RFC-5321 has this to say regarding status codes returned
>>> post-DATA
>>> 
>>>    When an SMTP server returns a permanent error status (5yz)
>>> code after    the DATA command is completed with
>>> ., it MUST NOT make    any subsequent attempt to
>>> deliver the message.  As with temporary    error status
>>> codes, the SMTP client retains responsibility for the
>>> message, but SHOULD not again attempt delivery to the same
>>> server without user review of the message and response and
>>> appropriate intervention.
>>> 
>>> I do not understand the reasoning behind the "SHOULD not", as
>>> I believe it should rather be a "MUST NOT" to maintain
>>> consistency. What am I missing?
>> 
>> (Personal opinion, not as editor or anything else because I
>> don't remember the original discussion any more). 
>> 
>> The key part of that text is the last part of the sentence:
>> "without user review of the message and response and
>> appropriate intervention".  Now the question for you is "are
>> you sure those are all of the cases".  If, for example, for
>> some messages, and automated review would be satisfactory, do
>> you think whatever robotic process was involved would
>> constitute "user review".  If the answer to either of those
>> questions is "no", then SHOULD is appropriate and the
>> question becomes whether there should be an explanation in
>> the text about those other possible cases.  (Now slipping my
>> editor hat back on, for this case, I hope not.)
>> 
>> best,
>>    john
>> 
>>  
>> 
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>> 
> 
> 
> --