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Re: Greylisting Query

From: Lydiard (lydiardspamcop.net)
Date: Tue Apr 08 2008 - 10:13:53 CDT


----- Message from Victor.Duchovnimorganstanley.com ---------
     Date: Tue, 8 Apr 2008 00:20:46 -0400

> On Tue, Apr 08, 2008 at 05:54:35AM +0200, Lydiard wrote:

>> And in fact where the user was valid, postfix ended up doing the DNS
>> lookups on the RBL. Surely not what greylisting was intended for, so
>> what have I still got wrong? :(
>
> http://www.postfix.org/postconf.5.html#defer_if_permit
>
> Why defer mail that you are going to reject?
>

> Especially, for an unknown recipient. If you want greylisting
> to be immediate, configure policyd to return "DEFER" instead of
> "DEFER_IF_PERMIT".

You're right of course. Thanks for the explanation. I guess I
installed greylisting to stop processing hordes of spam (with
expensive myqsl user and DNS RBL lookups) on the basis that spammers
won't retry and the other's will. So whilst there's no good reason to
defer something that would ultimately be rejected, deferring
immediately would a) free up some resources and b) give me a clearer
idea of where the serious/corporate spammers are (i.e. the ones who
retry).

Thanks again.

Lydiard