http://www.digitalfaq.com/forum/guides-ispconfig/3261-how-optimize-ispconfig.html

vi /etc/postfix/main.cf

# content_filter = amavis:[127.0.0.1]:10024

# receive_override_options = no_address_mappings

/etc/init.d/postfix restart

/etc/init.d/clamav-daemon stop 

/etc/init.d/clamav-freshclam stop 

/etc/init.d/spamassassin stop

/etc/init.d/amavis stop

update-rc.d -f clamav-daemon remove 

update-rc.d -f clamav-freshclam remove 

update-rc.d -f spamassassin remove 

update-rc.d -f amavis remove