[AusNOG] Greylisting in an ISP / Hosting Environment

[James Andrewartha]

On Mon, 4 May 2009, Trent Lloyd wrote:
> On 04/05/2009, at 4:01 PM, Andy Davidson wrote:
> > I use exim and only greylist borderline spam.  This way I get most of
> > my legitimate email straight away and only spam suspects get slowed
> > down.
> 
> Unfortunately that approach would kill one of the benefits of  
> greylisting.
> 
> Most implementations do it before the data portion, and thus you save  
> the traffic of being sent the email, and processing it with your anti  
> spam software.

My solution is to greylist on RBL failure only, using whitelister and 
postgrey for postfix. I also use fail2ban to temporarily block hosts that 
get greylisted 10 times in a row, although I'm not sure how effective this is.

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