The switch to qpsmtpd does seem to have reduced my spam intake somewhat, so out of curiousity I looked at the statistics from 2 years of procmail logs to see what’s been happening in terms of filtering effectiveness.
A quick import and bug-fix of Log::Procmail into OpenBSD, and some lashed up Perl and gnuplot later, the graph on the right showed up. The red and green are ham and spam respectively, as classified by SpamAssassin.
The large amount of ham in 2004 was not actually real mail, but mostly postmaster bounces from forged spam; I am currently forced to destroy all domain bounces without even reading them due to the sheer volume. This is something that Sender Permitted From promises to help solve once we determine if any our users send
@recoil.org mail from sources other than our mail server.
Since the turn of this year the amount of spam has jumped, but more concerningly, SpamAssassin has been missing increasing amounts, and it’s been flowing through straight to my Inbox (despite sa-update running daily). I’m going to do these graphs again in a few months and see just how much the switch to the new paranoid SMTP has helped.