Background: I run a small postfix/dovecot server on my site server. Just a handful of careful users. My spam folder would only have about 10-30 messages a day marked as spam by spamassassin. Server's running denyhosts to help block bad actors.
Recently checked my logs and noticed that the rbl checks in postfix or SA were sometimes getting blocked. So I finally installed a caching DNS server. Suddenly the spam that gets to my spam folder is down to five or so a day. Seems postfix is dropping a lot of connections due to RBL checks before they even get to SA. Are the RBLs that good? Is it crazy to worry that not enough spam is getting to my spam folder? :-)
