We want to do a Server Setup to Send bulk email 5,00,000 per day at around 50,000 mails/hour. Currently we have interspire setup as front end and exim MTA as backend to sendout Email. It's already setup SPF, DKIM, Domain Keys etc., still unable to achieve good deliverability. And the Message sending rate by exim is very slow. need your help in Optimizing the MTA for good performance and Increasing the Inbox Delivery. Looking atleast to get 3% - 4% open Rate. Thanks.