From: John Leslie
...
- local administrative choices that keep bastion SMTP servers ignorant
of per-user filter preferences
This is a feature, not a problem. If the end user wants a filtering
process individualized that much, s/he should choose to use a SMTP
server which agrees to do so.
That is a feature only if the user accepts the consequences of discarding
mail without generating bounces, including not informing senders of false
positives. Bounces from internal spam filters (either in MUAs or MTAs
inside organizations) are a major source of unsolicited bulk mail or spam.
- filtering at the DATA command requires either (1) rejecting for
all or no targets or (2) accepting for all targets and siliently
discarding the message for those targets that want it filtered.
Alternatively, the receiving SMTP server could reject any multiply-
addressed email.
People running SMTP servers that handle 100K or more msgs/day have
been uniformly horrified when I've suggested that. I don't really
understand why, but I have given up on the idea.
(Silently discarding _is_ a bad idea, when done by the SMTP server
itself. IMHO, it's better to mark for later discard -- which actually
could be done in such a way as to mark only for those recipients who
requested the more restrictive filtering.)
A better positition is that everything should be logged, particularly
including discarded mail, and in that case, enough of bodies to allow
targets to identify senders and the nature of the discarded messages.
Of course, one should assume users won't normally look at those logs.
Spam you read is not filtered, but at most categorized and stigmatized.
Vernon Schryver vjs(_at_)rhyolite(_dot_)com