Michael Stevens <mstevens@???> said, in message
20140218112200.GC783@???:
>
> I used greylisting for a while, but I found too many false positives
> (for me) with sites that are "legit" but don't work with it. Generally
> it seemed to be situations like big sites that would retry from one
> of a cluster of MTA boxes.
We discovered the cluster issue back in 2003 when testing the theory. My
solution was to just use the sender/recipient address as the key,
rather than sender/recipient/IP. I also wired in a pattern match to try
to strip out VERP from addresses so they get a free pass through the
greylisting.
Here's what I wrote back in December 2003, after we'd had
greylisting in place for 3 months:
http://users.aber.ac.uk/auj/spam/greydesc.cgi
We kept the system in place for just shy of 10 years and only got
rid of it when we outsourced mail to Microsoft. It was pretty much
self-maintaining.
Cheers,
Alun.
--
Alun Jones, auj@???, 01970 622494
Gwasanaethau Gwybodaeth / Information Services
Prifysgol Aberystwyth / Aberystwyth University
