I haven’t been getting any SPAM lately, so I thought I’d turn on catch-all to see what happens. Accepting mail for invalid recepients (e.g. anything @mydomain) caused about twice as much SPAM to be attempted, but still nothing got through to my Inbox:
------------------------------------ Stats for Feb 2010 ------------------------------------ Ham SpamC SpamR SpamM HamC 192 126 1951 0 0 -------------------------------------------------------------- 2269 Total messages 2077 Total Spam (Caught + Missed + Rejected) 91.53% Spam as % of all mail 93.93% % of Spam rejected by Postfix at SMTP time 0% False positive rate (Ham misclassified as Spam) 0% False negative rate (Spam misclassified as Ham) 100.00% Spam catch rate (Spam filter accuracy) --------------------------------------------------------------
As you can see, Postfix got most of it, then SpamAssasin got the rest. I heart Postfix and SpamAssassin. 
Dec 09 was the first month I had achieved 100% spam catch rate since I started filtering my own mail a few years ago. Thanks, SpamAssassin Bayes plugin! Merry Xmas to you as well!
------------------------------------ Stats for Dec 2009 ------------------------------------ Ham SpamC SpamR SpamM HamC 160 392 1273 0 0 -------------------------------------------------------------- 1825 Total messages 1665 Total Spam (Caught + Missed + Rejected) 91.23% Spam as % of all mail 76.45% % of Spam rejected by Postfix at SMTP time 0% False positive rate (Ham misclassified as Spam) 0% False negative rate (Spam misclassified as Ham) 100.00% Spam catch rate (Spam filter accuracy) --------------------------------------------------------------
Cooked up a little shell script to produce monthly email statistics such as amount of email received, how much of it was spam, percentage of spam correctly identified, etc. Previously, I had manually ran the numbers and input into OpenOffice Calc to get the stats — boring!
Example output:
root@dpork:~# spam-stats-month Aug 2009 ------------------------------------ Stats for Aug 2009 ------------------------------------ Ham SpamC SpamR SpamM HamC 151 122 3444 7 0 -------------------------------------------------------------- 3724 Total messages 3573 Total Spam (Caught + Missed + Rejected) 95.94% Spam as % of all mail 96.38% % of Spam rejected by Postfix at SMTP time 0% False positive rate (Ham misclassified as Spam) .18% False negative rate (Spam misclassified as Ham) 99.80% Spam catch rate (Spam filter accuracy) --------------------------------------------------------------