The problem that I have is SpamAssassin low detecting rate for spam. It was supposed to be highly increased by using SpamHaus ZEN which I am not sure it is used since detection is too low, so I would like to test with Protected Sky's RBL.
In order to compare the low detecting rate, I have a UTM (Debian based) before virtualmin that uses SpamAssassin to filter spam. UTM is dropping spam messages with score 4 or above, and marking as spam those with score 3 or above. Those marked as spam are reviewed again by Virtualmin, yesterday 1 of 23 was detected again as a spam by Virtualmin (I changed the settings after 10 mails so it may be more accurate to say 1 of 13 or 7% detection rate. Today at 8am from 7 messages marked as spam by UTM, Virtualmin detected only 2, or about 28% detection rate compared to UTM.
Currently my UTM does not allow me to set drop at 3.7 spam level which will eliminate most spam safely with current settings.
Anyway I would like to improve SpamAssassin detection rate. How may I be sure SpamHaus ZEN is used and also how can I add Protected Sky's RBL?
Comments
Submitted by andreychek on Wed, 04/13/2016 - 09:14 Comment #1
Howdy -- One thing you may want to consider is to enable grey listing (which can be done in the Email Messages) section. Grey listing can make a big difference in how much spam gets through.
As far as using RBL's goes -- I personally added SpamHaus to Postfix. What I did is edit /etc/postfix/main.cf, and on the "smtpd_recipient_restrictions" line, I added "reject_rbl_client sbl.spamhaus.org" to that line, and then restated Postfix.
Now, that's just the SBL, you could change it to use "Zen" if you prefer. I'm not familiar with Protected Sky, but if that's an RBL you should do something similar with them.