In the past, a company that uses Office 365 was required to restrict the access to the URL’s and IP’s addresses only to the datacenter where the O365 tenant was created, but nowadays this has changed (unless your company is using a special version of O365).
Currently, mots of the O365 services uses Geo-DNS, which means that if your company has users that travels between regions, so these users when request for a service will be connected to the closest datacenter. This process has be done to provide to the users a better experience while using O365 services.
But if you still need to filter the traffic, you can use the following url: https://support.office.com/en-us/article/Office-365-URLs-and-IP-address-ranges-8548a211-3fe7-47cb-abb1-355ea5aa88a2?ui=en-US&rs=en-US&ad=US to filter IP Addresses in terms of services that your company needs
Albandrod's Memory 