Re: Didn't receive the original post (to which this was a reply)

From	Joe <joe@jretrading.com>
Newsgroups	linux.debian.user
Subject	Re: Didn't receive the original post (to which this was a reply)
Date	2026-04-30 19:10 +0200
Message-ID	<MPD3H-1zF5-3@gated-at.bofh.it> (permalink)
References	(3 earlier) <MOV2F-15Wi-11@gated-at.bofh.it> <MOW8p-16BI-3@gated-at.bofh.it> <MOWBr-16Me-1@gated-at.bofh.it> <MOY0x-17PV-1@gated-at.bofh.it> <MP6AN-1dEL-1@gated-at.bofh.it>
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On Wed, 29 Apr 2026 07:12:55 +0100
Chris Green <cl@isbd.net> wrote:

> Stefan Monnier <monnier@iro.umontreal.ca> wrote:

> > 
> > I think the answer lies in the definition of "discard" and at which
> > stage this can happen.  Like all MTAs, Gmail routinely silently
> > drops email on the floor on the basis that it's presumed to be
> > "spam". So Google's employee must have been referring to something
> > else, like "discarding after spam filtering" or something like that.
> >   
> Is that really true?  

Think about it. SMTP was designed as a 'reliable' protocol (don't laugh)
whereby if for any reason an email cannot be delivered, the sender
will be notified that it didn't get through.

Once SMTP servers started refusing connections from dodgy senders (no
PTR record, no complementary A/PTR pair, etc.) it was realised that some
SMTP servers would still accept the mail. Forging the From: header to
the real target of the spam would cause this person not to be found by
the gullible SMTP server, so it would bounce the *entire* spam message
'back' to the alleged sender. The bounce came from a 'legitimate'
sender, so was accepted by the intended target SMTP server and
delivered to the recipient.

This was made worse by the typical management insistence that *all*
email be accepted. The first line of defence for an SMTP server is to
reject at SMTP transaction time any email addressed to a non-existent
recipient. When management insisted that they must accept all email to
avoid losing a potential order with a typo in the recipient name, this
line of defence was abandoned.

Many large organisations started routing incoming email through a
spam-cleaning service, which almost never had a list of genuine
recipients, so this made the problem worse.

Things are much better now, a few years ago my server was rejecting
7000-10000 unroutable addresses a day, mostly the same few suspects
running though the same list of obviously made-up recipient names day
after day, for years at a time. Now it's two or three a day.

Anyway, the point of all this is to show there was a real problem with
'relay' or 'reflected' spam, and all the 'accept anyone' servers could
do was to try to identify the spam emails with unroutable addresses and
refuse to bounce them, i.e. silently discard them. Identification was a
bit hit-or-miss, so the systems normally applied the benefit of the
doubt and did bounce some spam.

The sender verification systems now pretty much eliminate spam from
hacked domestic computers, so the problem should mostly have gone
away, but I wouldn't be surprised if some email systems are still
silently dropping email identified as spam, whether sent to a genuine
recipient or not. Nobody wants spam.

-- 
Joe

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Moribund mailing list CGS <etphonehomefrance@gmail.com> - 2026-04-28 17:10 +0200
  Re: Moribund mailing list Norwid Behrnd <nbehrnd@yahoo.com> - 2026-04-28 17:30 +0200
    Re: Moribund mailing list "Jeremy Nicoll" <jn.ml.dbi.73@letterboxes.org> - 2026-04-28 19:20 +0200
      Re: Moribund mailing list David Wright <deblis@lionunicorn.co.uk> - 2026-04-28 20:20 +0200
        Re: Moribund mailing list "Jeremy Nicoll" <jn.ml.dbi.73@letterboxes.org> - 2026-04-28 20:40 +0200
          Re: Moribund mailing list Andy Smith <andy@strugglers.net> - 2026-04-28 21:50 +0200
          Re: Moribund mailing list David Wright <deblis@lionunicorn.co.uk> - 2026-04-29 01:00 +0200
            Re: Moribund mailing list "Jeremy Nicoll" <jn.ml.dbi.73@letterboxes.org> - 2026-04-29 01:40 +0200
  Re: Moribund mailing list Felix Miata <mrmazda@earthlink.net> - 2026-04-28 17:50 +0200
    Didn't receive the original post (to which this was a reply) (was: Re: Moribund mailing list) rhkramer@gmail.com - 2026-04-28 18:30 +0200
      Re: Didn't receive the original post (to which this was a reply)  (was: Re: Moribund mailing list) Nicolas George <george@nsup.org> - 2026-04-28 19:30 +0200
        Re: Didn't receive the original post (to which this was a reply) (was: Re: Moribund mailing list) rhkramer@gmail.com - 2026-04-28 21:50 +0200
      Re: Didn't receive the original post (to which this was a reply)  (was: Re: Moribund mailing list) Andy Smith <andy@strugglers.net> - 2026-04-28 20:10 +0200
        Re: Didn't receive the original post (to which this was a reply)  (was: Re: Moribund mailing list) Jan Claeys <lists@janc.be> - 2026-04-28 21:20 +0200
          Re: Didn't receive the original post (to which this was a reply) nwe <nwe@gitcoding.net> - 2026-04-28 21:50 +0200
          Re: Didn't receive the original post (to which this was a reply)  (was: Re: Moribund mailing list) Andy Smith <andy@strugglers.net> - 2026-04-28 21:50 +0200
            Re: Didn't receive the original post (to which this was a reply)  (was: Re: Moribund mailing list) Joe <joe@jretrading.com> - 2026-04-28 23:00 +0200
              Re: Didn't receive the original post (to which this was a reply)  (was: Re: Moribund mailing list) Nicolas George <george@nsup.org> - 2026-04-28 23:20 +0200
                Re: Didn't receive the original post (to which this was a reply) Nicolas George <george@nsup.org> - 2026-04-28 23:30 +0200
                Re: Didn't receive the original post (to which this was a reply) nwe <nwe@gitcoding.net> - 2026-04-29 00:00 +0200
                Re: Didn't receive the original post (to which this was a reply) Nicolas George <george@nsup.org> - 2026-04-29 11:10 +0200
                Re: Didn't receive the original post (to which this was a reply) nwe <nwe@gitcoding.net> - 2026-04-28 23:30 +0200
                Re: Didn't receive the original post (to which this was a reply)  (was: Re: Moribund mailing list) Joe <joe@jretrading.com> - 2026-04-29 09:10 +0200
                Re: Didn't receive the original post (to which this was a reply)  (was: Re: Moribund mailing list) Nicolas George <george@nsup.org> - 2026-04-29 11:10 +0200
              Re: Didn't receive the original post (to which this was a reply)  (was: Re: Moribund mailing list) <tomas@tuxteam.de> - 2026-04-29 12:00 +0200
              Re: Didn't receive the original post (to which this was a reply) (was: Re: Moribund mailing list) "Roy J. Tellason, Sr." <roy@rtellason.com> - 2026-04-29 18:50 +0200
                Re: Didn't receive the original post (to which this was a reply)  (was: Re: Moribund mailing list) Nicolas George <george@nsup.org> - 2026-04-29 19:00 +0200
            Re: Didn't receive the original post (to which this was a reply) Stefan Monnier <monnier@iro.umontreal.ca> - 2026-04-28 23:20 +0200
              Re: Didn't receive the original post (to which this was a reply) Chris Green <cl@isbd.net> - 2026-04-29 08:30 +0200
                Re: Didn't receive the original post (to which this was a reply) Joe <joe@jretrading.com> - 2026-04-29 09:00 +0200
                Re: Didn't receive the original post (to which this was a reply) Stefan Monnier <monnier@iro.umontreal.ca> - 2026-04-30 17:50 +0200
                Re: Didn't receive the original post (to which this was a reply) Joe <joe@jretrading.com> - 2026-04-30 19:10 +0200
                Re: Didn't receive the original post (to which this was a reply) Greg Wooledge <greg@wooledge.org> - 2026-04-30 20:00 +0200
                Re: Didn't receive the original post (to which this was a reply) Joe <joe@jretrading.com> - 2026-04-30 20:40 +0200
                Re: Didn't receive the original post (to which this was a reply) Greg Wooledge <greg@wooledge.org> - 2026-04-30 21:20 +0200
              Re: Didn't receive the original post (to which this was a reply) CGS <etphonehomefrance@gmail.com> - 2026-04-30 16:50 +0200
            Google employee expertise (was: Re: Didn't receive the original post (to which this was a reply) (was: Re: Moribund mailing list)) rhkramer@gmail.com - 2026-04-30 16:00 +0200
              Re: Google employee expertise (was: Re: Didn't receive the original post (to which this was a reply) (was: Re: Moribund mailing list)) rhkramer@gmail.com - 2026-05-01 02:30 +0200
                Re: Google employee expertise (was: Re: Didn't receive the original  post (to which this was a reply) Thomas Dineen <tdineen2021@gmail.com> - 2026-05-01 22:20 +0200
                On tolerance [was: Google employee expertise ...] <tomas@tuxteam.de> - 2026-05-02 07:40 +0200
      Re: Didn't receive the original post (to which this was a reply)  (was: Re: Moribund mailing list) Jeffrey Walton <noloader@gmail.com> - 2026-04-28 21:10 +0200
        Re: Didn't receive the original post (to which this was a reply)  (was: Re: Moribund mailing list) Joe <joe@jretrading.com> - 2026-04-28 21:30 +0200
      Re: Didn't receive the original post (to which this was a reply)  (was: Re: Moribund mailing list) Anders Andersson <pipatron@gmail.com> - 2026-04-28 21:30 +0200
      Re: Didn't receive the original post (to which this was a reply) Richmond <dnomhcir@gmx.com> - 2026-04-28 22:20 +0200
        Re: Didn't receive the original post (to which this was a reply) rhkramer@gmail.com - 2026-04-28 22:30 +0200
  Re: Moribund mailing list Radhitya <alif@radhitya.org> - 2026-05-01 15:50 +0200

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