ietf-smtp
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Re: Processing after the end of DATA

2010-08-09 19:39:44


On Aug 9, 2010, at 5:10 PM, Dave CROCKER wrote:


G'day.

It's Monday.  I'm feeling aggressive...

Once upon a time, it was deemed important to respond after crlf.crlf as quick 
as possible.  Pausing for additional processing of varying complexity and 
delay was deemed unacceptable.

There seems to be an emerging constituency that thinks this stricture is not 
applicable to modern email services.

I did a 10-second scan of 5321 and didn't find the relevant text, but I'd 
like to resolve -- and preferably squash -- this issue quickly.

Can folks offer pointers to normative language?

Tail end of section 6.1 of 5321:

"To avoid receiving duplicate messages as the result of timeouts, a
   receiver-SMTP MUST seek to minimize the time required to respond to
   the final <CRLF>.<CRLF> end of data indicator. "

However the same section also says:

  "if there is a delivery failure after acceptance of a message, the
   receiver-SMTP MUST formulate and mail a notification message"

If you're doing any useful level of spam / virus filtering then your
only option which will comply with both of those requirements
will be to send a notification to the reverse-path - which in the case
of the vast majority of spam and virus-laden email, is an unrelated
third party.

Cheers,
  Steve