I would like one of my domains to be configured in such way that 50% of my mail users should be hosted on MS Office 365 & balance 50% users to be hosted on MS Exchange. That way we can use our Smarter Mail server and eWall to do spam / virus cleaning before forwarding mails to office 365/MS exchange. How can this be done?
This is a tricky problem -- primarily because of the routing involved -- normally email for a given domain would all be delivered to the same platform. SmarterMail lacks the routing features you need for this, but you're on the right track. Most large scale filtering systems separate the filtering process from the delivery process to improve scalability and reduce security concerns. To help filter emails in the way you require, try using Communicate Pro server used as a gateway with SNF4CGP on that server to do your filtering. Then you can use CGPs extensive rule processing abilities to deliver the filtered messages to the various MDAs you have in mind. You may be able to use Communigate's community edition since you won't be adding mailboxes to your filtering server(s).
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