I had great results from grey-listing but my users didn't like
having to wait 30-60-90 minutes for mail, and I understand that. When
you're on the phone with someone and they say "Just sent it," they
expect you to have it in a matter of seconds. As I'm often in that
positition, I had to support that view and remove the grey-list.
I use sa-exim, which means I can greylist after the message has been
scored. So I only greylist a message if it scores over 7 and toss
messages over 20.
This way the vast majority of messages are sent through instantly.
I've tried aboslute RBL blocking, but I'm happier having RBL as a
weighted factor counting for or against the spamminess of an email.
We only process about 5,000 non-spam messages per day (out of about
45,000/day total) and are doing OK on a couple of old dual-processor
systems running it through clamd and spamd with sendmail.
Same here. Sure its more cpu power, but it lowers false positives. CPU
cycles are cheap.
