Hello folks,
This page never gets old and it has a comprehensive list of all services, ports and protocols in use by Office365. This page should be on your bookmarks if you have office365 and want to restrict more your access to the service.
https://support.office.com/en-gb/article/Office-365-URLs-and-IP-address-ranges-8548a211-3fe7-47cb-abb1-355ea5aa88a2?ui=en-US&rs=en-GB&ad=GB