Use fail2ban for global blocking. With Postfix 3.x, you can also use smtpd_client_auth_rate_limit to limit the number of AUTH commands per client IP address.
Wietse
Use fail2ban for global blocking. With Postfix 3.x, you can also use smtpd_client_auth_rate_limit to limit the number of AUTH commands per client IP address.
Wietse