[Mailman-Users] Mailman Hosting

[Odhiambo Washington]

On 23 December 2016 at 17:36, Richard Shetron <guest2 at sgeinc.com> wrote:

> Maybe they were using some type of grey listing.
>
> For those who don't know:
> Grey listing is where the target MTA rejects with a retry error code the
> email from a new source for some period of time.  Every site can set their
> own delay.  Most spammers won't retry so it gets rid of a lot of spam.
> Real email servers will accept the retry error (4xx) and retry after some
> prefigured time from a few seconds to an hour or more.  The IP addresses
> are tracked and if retried after the time limit are white listed for
> anywhere from a few hours to a month or more.
>

I know Exim will only treat a session as a failure if it gets 5xx. Does
Postfix do the same?


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Best regards,
Odhiambo WASHINGTON,
Nairobi,KE
+254 7 3200 0004/+254 7 2274 3223
"Oh, the cruft."