On 8/23/2011 2:25 PM, Wietse Venema wrote: > Stan Hoeppner: >> On 8/23/2011 9:10 AM, Kov?cs J?nos wrote: >>> Thanks Ralf! It's amazing how much spam the pregreet test and a good RBL >>> can catch. >>> Do you have any data on how many spam emails survived postscreen? >> >> Overall, Postscreen is no better nor worse at stopping spam than what >> we've all been doing via SMTPD for many years. It simply decreases the >> number of SMTPD processes required to do so, hence decreasing server >> load and allowing more processing of legitimate mail. >> >> Postscreen is no magic bullet, it's overall "catch rate" being little >> different than setups without Postscreen. > > Agreed. Postscreen's main goal is to reduce mail server load, so > that you can postpone that forklift upgrade. > > Postscreen also stops a few percent of spambots that popular DNSBLs > miss, but at this time, that is only a minor benefit.
I would think the proper metric for evaluating the success of Postscreen deployment should be something like mx_#smtpds_per_connect_per_day_week_month vs the period before deploying Postscreen; load average before and after Postscreen, Postfix memory consumption, etc. It would include no spam catch/miss/false positive/negative data as the difference between before/after would likely be within statistical margin of error. Has anyone compiled such data? If so and I missed it, apologies for having my head in the sand. -- Stan
