juan smitt: [using smtpd_client_connection_count_limit for traffic management] > Unfortunately the service (which is made of 4 servers) is behind a > firewall which hides the real client IPs so these 4 servers see only 1 > client (the firewall) and the expected mail count is 4+ million per > day.
This is a terrible idea, because the server cannot distinguish between different clients, and therefore you can't 'punish' a bad client with client-based policies. You punish them all. Please consider using something like HaProxy, which can inform Postfix of the remote SMTP client IP address and thus enables more meaningful policies. Wietse