On Sun, Jun 07, 2020 at 05:53:28AM -0700, John Pierce wrote:
> On Sun, Jun 7, 2020, 2:47 AM Nicolas Kovacs <info@xxxxxxxxxxxxx> wrote:
>
> > ....
> > My aim is simply to eliminate as much spam as possible (that is, before
> > adding
> > SpamAssassin) while keeping false positives to a minimum.
> >
>
> The one thing that stopped the most spam on my last mailserver was
> greylisting. Any mta that connects to you to send you mail, you check
> against a white list, and if they are not on it, you reject the connection
> with a 'try again later' code and add them to a grey list that will let
> them in after 10 minutes or so. The vast majority of spambots don't queue
> up retries, they just move on to the next target.
>
> The downside of greylisting is delayed delivery of mail from non white
> listed servers, dependent on their retry cycle.
I hit another limitation. My backup MX handler is a 3rd party who
will not use greylisting. Thus all the 1st timers I rejected just
delivered to my alternate MX address and were not blocked at all.
Jon
--
Jon H. LaBadie jcu@xxxxxxxxxx
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