occasionally looks at the results of Spamassassin’s nightly masscheck at RuleQA in order to analyze the performance and safety of add-on DNSBL’s.  It is vitally important to know how a DNSBL is performing before adding it to your Spamassassin custom rules.  Our analysis demonstrates that raw detection numbers alone can be misleading, as ham safety ratings and overlaps with other rules must be taken into consideration before you decide to use a particular add-on rule.

Today’s report shows some big changes since our previous report from January 2011 where some previously good rules have turned bad. Examined below are Hostkarma, SpamEatingMonkey, Tiopan, UCEProtect, Mailspike, Nix Spam and Lashback UBL.  Recommended scores below are what I personally use in production.