[Mailman-Users] excessive bounce notifications..

Brad Knowles brad at shub-internet.org
Sun May 18 19:00:02 CEST 2008

On 5/18/08, Mark Sapiro wrote:

>  For my server, I use Postfix as the incoming MTA with Postgrey for
>  greylisting. This gets rid of much spam.

At the Anti-Spam Workshop at the LISA'07 conference, one lesson we 
learned is that every site is different, and what works for one site 
may not work for another.

However, another thing we learned is that greylisting is becoming 
much less effective for many sites -- the workshop leader shared with 
us some average statistics for greylisting success versus spam for 
the year versus the last month, and the year was a 20% hit ratio 
while the last month was 10%.

At that point, I would say that greylisting is less than useful. 
There's a definite non-zero cost to using it, but if the spammers are 
doing non-queueing retries, then greylisting becomes less than useful.

>                                            The remaining mail is run
>  through MailScanner <http://mailscanner.info/> which in my
>  configuration uses ClamAv, SpamAssassin, Razor, Pyzor, DCC and other
>  checks for malware and spam. I find this to be a pretty effective
>  combination.

I've got a multi-part article I've been writing for a couple of years 
that details all of my knowledge and experience on the subject of 
fighting spam (and I've been doing this for over seventeen years), 
for publication on the LOPSA.org website, and goes into some detail 
on the anti-spam methods we use for python.org.

Anyone who wants a copy of the current draft should contact me, and 
I'll be glad to share it with them, under the conditions that they 
don't share it with anyone else without my prior approval, and they 
promise to give me feedback.

I'm also hoping to do an invited talk at the LISA'08 conference on 
one small part of the spam problem, if anyone is interested.

Brad Knowles <brad at shub-internet.org>
LinkedIn Profile: <http://tinyurl.com/y8kpxu>

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