Q. I want to use Office 365 but use a web filtering system. What IP address ranges and names does Office 365 use so I can add the required exceptions?
A. Microsoft maintains a page that shows all the domains and IP address ranges that are used by the various Office 365 services. This can be viewed at https://technet.microsoft.com/en-us/library/hh373144.aspx. Note that these IP address ranges and even domain names may change and at the top of the referenced page is a RSS feed subscribe link which will enable you to be notified of domain name and IP address changes enabling your internal filtering to be updated as required.