Author: Chris Knadle Date: To: exim-users Subject: Re: [exim] Exim outgoing emails throttling
On Monday, July 23, 2012 11:58:58, David Woodhouse wrote: > On Tue, 2012-07-17 at 11:19 -0400, Chris Knadle wrote:
> > > * Recipient address rejected: Greylisted for 2 minutes
> > > ...
> > > Probably DNS, RDNS or SPF issue. right or wrong ?
> >
> > I don't think this is RDNS or SPF is related.
>
> It might be. Any half-sane greylisting implementation will have to have
> some *reason* for greylisting the messages. Lack of reverse DNS is
> certainly something that triggers greylisting on my systems.
>
> You could also imagine people using SPF as a trigger — either an SPF
> failure causing greylisting to happen, or an SPF 'pass' causing it to be
> avoided. It's one of the few things that SPF might actually be useful
> for.
The two greylisting implementations I'm familiar with, greylistd and postgrey,
don't seem to have any configuration options related to RDNS or SPF. As far
as I can tell they both operate solely on whether there is already an entry
for the sender emailing the recipient, otherwise a temporary rejection is done
to force the sending mailserver to retry. There are configuration options for
the minimum wait time for accepting a retry and the length of time to hold
greylist entries before they expire.
