we've inherited the DNS from another ISP and now our mail server is bombed by about 1000 emails per minute, 99.99% of these emails are just spam. We're trying to optimize the filtering/rejecting the spam with no much luck.
What would be on your opinion the optimal set for
The system config: Ubuntu + Amavis + Postfix + MySQL + Fail2Ban-Postfix
Any advise is welcome!
On alteration of the posftix configuration as folows and configuring the Potrgey service the spam level decayed 10 times
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_non_fqdn_hostname, reject_invalid_hostname, reject_non_fqdn_sender, reject_unknown_sender_domain, reject_non_fqdn_recipient, reject_unknown_recipient_domain, check_policy_service inet:127.0.0.1:10023, reject_rbl_client zen.spamhaus.org, check_recipient_access mysql:/etc/postfix/mysql-virtual_recipient.cf, reject_unauth_pipelining, reject_unauth_destination