This may not be the right place to discuss this, as it is a generic anti SPAM query, but please indulge and point me to where answers might be found. Or, just answer if you feel inclined. After this mornings SPF discussion . . . well, I'll ask anyway.
An organization I know of is moving to o365 from their own mail system. For a variety of reasons, the migration cannot be completely resolved "day one". Thus, we concocted a scheme of keeping MX as is, and having the current system simply relay messages to o365 and have users start using o365 right away. Everyone thought this a great idea, solving several issues, until, suddenly, last evening, I realized that we would be sending email that might appear "spoofed". That is, from IP's that are not published as "ours". I've not run this by any one else yet, hoping to either allay my concerns, or raise the alarm and have some suggested solutions, by asking a well versed group. joe a.
