On Wed, 15 Oct 2008, Sanford Whiteman wrote:
I don't need to. Some 5xx codes, like 551, *are* already advisory in
rfc2821. It just means "can't deliver it that way, but try this other
way". 551 has been proposed as an alternative to SRS.
Nowhere in 2821 is 551 treated as anything but a permanent error. It
continues to be a "Permanent Negative Completion reply" in the 5yz
range. 551 is noted as more correctable -- *via a new message
envelope* -- than other permanent errors. By definition, any such
As it says above your response it is only permanent *for that recipient*.
A new message envelope - or a web query - is exactly what we are talking
about. With C/R (which I don't use - I'm just objecting to your rants)
the 5xx (or DSN) is in some sense a lie: the message is stored someplace. It
just won't be delivered until some event unrelated to SMTP takes place.
551 says delivery to that recipient is dead in the water - but suggests
another recipient to use instead.
I believe that. I have many colleagues that do boutique anti-abuse
hosting that do a better job than the big guys as well. But none of
them, including you, use C/R to do it. And you wouldn't be any more
likely to be able to get away with C/R for your customer base if you
used this phantasmic envelope-time rejection idea.
I would never use C/R for a customer base. It is an option for
individuals who want to get only quality emails. But that is why
the current implementations are so bad. To send a proper DSN or
5xx requires hooks at the MTA level. Most people have some procmail
style script that sends a reply - aaaarrrrgggghhh! Now if MTAs would
only *support* (optionally) C/R schemes, then C/R backscatter would
not be such a problem.
--
Stuart D. Gathman <stuart(_at_)bmsi(_dot_)com>
Business Management Systems Inc. Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flammis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.
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