We've recently moved our company onto the Office365 platform and this is our first foray into using Exchange. For the most part everything is set up and functioning properly with our main company domain.
However, for a variety of reasons, we have kept our old mail server running as we need it for sending automated emails from our many legacy domain names. (Moving these domains to Office365 was not an option due to sending limits and services like MailGun and MailChimp haven't worked out for us)
An issue is we have many clients and old newsletter subscriptions that still send mail to our old legacy domains which end up on our old server. For now, we have all these old accounts simply forwarding to their appropriate Office365 account. This is working but we have to check multiple spam filters and other aggravations have arisen. We're wondering if there's a better way to set this up?
So, what we need is the old server to stay running with legacy domains for our automated processes to use to send. But, we want incoming mail for legacy domains to route to Office365.
Thanks for any suggestions.