Our organization is currently using Exchange on-line in the cloud (office 365).
We have an external vendor who would like to follow up with potential customers by sending emails on behalf of (or appear to be coming from) our organization and not theirs.
How can this be accomplished? They are running an on premise exchange system with outlook 2010 / 2013 as their client.
Can this be done by using a SPF record? If so, how?