OT - Greylisting (was: Re: gOCR SpamAssassin plugin)

[Michael Baird]

On Fri, 2006-08-11 at 09:09 -0800, Kevin Miller wrote:
> Michael Baird wrote:
> 
> > Greylisting decreases load immeasurably on a mailscanner system, the
> > cost of greylisting is much less then allowing the message to go
> > through the mailscanner sytem. I deployed it several months ago, it
> > really is a good tool, and I've had very few complaints (10000 users).
> 
> I just use Sendmails greet pause which is 10 seconds to set up and works
> a treat - does greylisting add significant control or improvement over
> that?  Anybody using them in tandom or is one or the other to be
> preferred?
Yes it does, I also use greet pause, they really are two entirely
different ideas. Sendmail's greet pause is looking for smtp clients that
don't follow RFC properly (send data without waiting for
acknowledgement), while Greylisting relies on receiving mail from proper
smtp servers (they are told to retry delivery in a time period). Most of
the rogue dictionary attacking virus spambots will ignore this, and will
get caught in the greylist.

It's an easy setup and low impact, hardly noticeable by clients (I set
my greylist time to 1 minute, with a 7 day whitelist). Just give it a
try, I've been really impressed with the results since I've been running
it.

I use the one from http://hcpnet.free.fr/milter-greylist/, with SPF
checks enabled.

Regards
Michael Baird