My goal was to disable amavis and clamav for lowering my RAM consumption. I've noticed this subject being covered in several forum posts and I've understood how it is done. The problem is does not work as expected. 1. Commented lines in /etc/postfix/main.cf - restarted postfix . I have followed the instructions here (faqforge.com/linux/controlpanels/ispconfig3/how-to-disable-spamfilter-and-antivirus-functions-in-ispconfig-3) When I sent a test email I found this in the logs "Sender address triggers FILTER amavis:[127.0.0.1]:10026; " I have found no trace of port 10026 in any postfix configuration files (main.cf / master.cf) 2. I tried commenting a reference on amavis in master.cf and restarting postfix according to the instructions here (question-defense.com/2009/12/26/remove-amavis-content-filter-from-postfix-configuration-requeue-all-postfix-email-messages) The same thing in the log messages, sender address triggers amavis. The curious thing Only after I reload the postfix configuration (postfix reload) and requeue emails (postsuper -r ALL) the emails are being sent - but only those that failed to be sent. If I send another email after reloading and requeing, I get the same problem of triggering the amavis filter. It only gets solved after manually requeing emails again. 3. Tried system reboot. Tried multiple service restarts (postfix, amavis). Same thing I don't understand Where is a reference of port 10026 in any postfix configuration? Why are emails being sent only after manual requeue ? I have a feeling that some configuration (maybe in ISPconfig3, I have no idea) overwrites some parameters in the post configuration. More info mail receiving log sample (triggered amavis on both 10024 and 10026 ports) - pastebin.com/EBMpvJWZ Any ideas ?