linux email server + office 365 cloud on a windows domain

[rmit]

Can i have a domain with office 365 on the cloud ( no on-premises exchange server) configured and at the same time have open source email server - Postfix, ( physical machine) on the domain as well. idea is to minimize licensing cost. i want important users to use office 365 on the cloud and the rest to use an open source email server ( postfix or any linux based server) whichever is applicable. I would want to protect my emails from spam by using email security product as well. is this setup possible at all and has anyone tried this .

 

[Mushkins]

Simply put- no.

Your DNS MX records would point to your spam filtering/security product, which then needs to forward those messages to one service or the other. Postfix does not integrate with Office 365 in that way, if you're dead set on having an on-premise mail server with your O365 service it *must* be a recent version of Microsoft Exchange.