[CentOS] Postfix restrictions

Sun Jun 7 12:53:28 UTC 2020
John Pierce <jhn.pierce at gmail.com>

On Sun, Jun 7, 2020, 2:47 AM Nicolas Kovacs <info at microlinux.fr> 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 finally gave up on running my own email services and use Gmail which has
excellent spam filtering

>