On 12/02/2021 22:18, Mathew Newton wrote:
On Friday, 12 February 2021 at 14:32:41 UTC, The Natural Philosopher wrote:

Dropping mail silently contravenes the protocol. But it is exactly what
big mail servers and spam filters do

How would you expect/prefer them to behave?
Bounce, or inform recipient

Given that large mail providers can't perform filtering during receipt of mail (i.e. whilst the SMTP dialogue is still underway)
They could if they wanted to

if a message is subsequently found to be spam it can't be sent back to
the purported sender as this is likely to fake and quarantining
everything doesn't really work for anyone (mail platform or recipient)
given the volumes involved.

I run a mail server and silently drop (as in don't deliver to the recipient or bounce) the 'spammiest of spam' and have never knowingly had a single false positive. I would expect large mail platforms to perform just as well. False positives for 'possibly spam' are few and far between these days too (and usually down to the poorly configured sender domains/software).



--
The biggest threat to humanity comes from socialism, which has utterly
diverted our attention away from what really matters to our existential
survival, to indulging in navel gazing and faux moral investigations
into what the world ought to be, whilst we fail utterly to deal with
what it actually is.