Milter-greylist

Matthias Scheler wrote:
> On Wed, Oct 12, 2005 at 06:26:54PM -0400, Matt Kettler wrote:
> 
>>My sendmail *does* reject nonexistent senders, and always has. re-read my
>>message. The rejection happens *AFTER* the greylist runs.
> 
> 
> You can change that behavior via "/etc/mail/access". Addresses which
> are blacklister there e.g. like this ...
> 
> To:foobar@...			error:5.1.1:550 User unknown
> 
> ... get refused immediately. My system automatically creates an
> access list based on the local accounts and alias and merges that
> into "/etc/mail/access".
> 
> 	Kind regards
> 

Matthias, how does that help against a dictionary attack?

You can't put all possible combinations of username into /etc/mail/access. The
access list would be infinitely large.