I am using ISPConfig for years now. It is a good management software for hosting servers. Not as good and stuffy as CPanel, but it will do the job.
Because we don’t have MailScanner out-of-box in ISPConfig and because I don’t want to configure it manually for all the websites, I decided to tune up the postfix.
Long story short, you have to do that:
1. Backup
cp -pf /etc/postfix/main.cf /etc/postfix/main.cf.bak
2. Add new features with postconf -e
postconf -e 'smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_invalid_hostname, reject_non_fqdn_hostname, reject_unknown_recipient_domain, reject_non_fqdn_recipient, reject_unauth_destination, reject_non_fqdn_sender, reject_unknown_sender_domain, reject_unknown_recipient_domain, reject_rbl_client cbl.abuseat.org,reject_rbl_client dul.dnsbl.sorbs.net,reject_rbl_client ix.dnsbl.manitu.net, check_recipient_access mysql:/etc/postfix/mysql-virtual_recipient.cf, reject_unauth_destination'
3. Restart postfix
/etc/init.d/postfix restart
Credits to faqforge.com
