Rejecting at SMTP time (Re: [Techtalk] Testing home mail server)

[Colleen Hatfield]

On Wed, 9 Feb 2005 11:33:35 +1100, Mary <mary-linuxchix at puzzling.org> wrote:
> On Wed, Feb 09, 2005, conor.daly at cod.utvinternet.com wrote:
> > The idea is that it will reject loads of spam at smtp time rather than loading
> > spamassassin with junk.
> 
> What are the reasons you're doing this? The most common one is "the
> bounce will go straight back to the spammer because it's happening at
> SMTP time, and they will realise my address is spam immune!"

I'd say the most compelling reason to do so is that you waste less of
your resources dealing with the spam.  If you can reject the spam
during the SMTP transaction (preferably as early as possible), less of
your bandwidth, disk space and server cycles are wasted on garbage.  I
think of it along the same lines as rejecting mail for non-existent
users, rather than queuing it and attempting to bounce it.

> I tend to prefer to accept and silently drop spam (and double for
> viruses!) for that reason: reject-at-SMTP-time is not some kind of
> magical direct link between you and the spammers.

Silently discarding mail is a pretty scary proposition to me without
being able to guarantee a 0% false positive rate.  Everyone has their
own preferred way of dealing with such things though ;-).

- Colleen