[vox-tech] postgrey is dangerous?

[Larry Ozeran]

Thanks Bill. More good information that I can use.

To those who prefer spam over SPAM, I have no personal preference, I don't particularly enjoy either ;-)

On 7/2/2008 at 12:30 AM Bill Broadley sent:

>Sorry to comment late, but I figured I'd throw my input in.
>
>First of all the idea behind grey listing is quite sound, it's an official 
>part of the SMTP standard and anyone who can't deal with it is running a 
>broken mail server that will fail in many real world scenarios that do not 
>involve greylisting.  A please try again later can come up for numerous 
>reasons, system load, maintenance windows, system failure, etc.
>
>I've found it to be rather effective, when combined with HELO filtering
>can be 
>quite effective at cutting down the amount of SPAM and makes it much
>easier to 
>run a mailserver that saves the most cpu intensive SPAM/Virus scanning for
>the 
>much reduced traffic that makes it through.  This graph is representative
>to what I saw:
>     http://postgrey.schweikert.ch/mailgraph_greylisting.png
>
>The compatibility from what I can see is pretty good, I've seen zero
>problems 
>with the bigger systems like yahoo, gmail and the like.  Sure some travel 
>agent running some wonky mailserver that he bought as a turnkey package
>from 
>some clueless company 5 years ago might have this incompatibility, but 10%
>of his email vanishes into the either because it doesn't handle SMTP
>properly 
>in many ways... but typically such folks adapt and will follow up from a
>gmail 
>account or something.  Real estate agents seem to have similar problems.
>
>Additional documentation for postfix is at:
>http://www.postfix.org/SMTPD_POLICY_README.html
>
>The above also includes a sample greylisting daemon if you don't want to
>use 
>postgrey.
>
>Other implementations at:
>http://www.greylisting.org/implementations/postfix.shtml