Re: MTAs denying messages
On 10/13/2014 4:21 AM, Joe <joe@jretrading.com> wrote:
> The intention is that the spam emails be accepted by a catch-all
> domain-wide mail server, then later bounced by the one that holds the
> mailboxes and knows the addresses are invalid.
And that, by definition, is backscatter, which will quickly (and
deservedly so) get you blacklisted if your mail server handles even a
moderate volume of mail, and eventually in any case.
> If the authoritative mail server for the domain knows the genuine
> recipients, it doesn't work, and that's the biggest single anti-spam
> measure possible.
No, that is one of many big mistakes that people new to administering
mail servers make.
Professional mail admins will virtually never, under any circumstances,
accept mail then later bounce it. I use the 'virtually' qualifier
because there may be some experienced admins who have tools that give
them a high level of confidence and they may bounce certain emails that
they know are legitimate, but for policy reason, they decide, after
having accepted it, that they do not want to deliver it - but they will
(and should) only do this for mail that they have as close to a 100%
certainty that the sender is legitimate (not forged), and this is very
hard to do, which is why 99+% simply won't do this.
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