Zscaler for Office 365 is the right answer
Zscaler 5.5 release is now deployed across Zscaler’s cloud delivering 50+ new features and enhancements. Zscaler now supports Microsoft recommended one-click Office 365 configuration. Zscaler monitors changing Office 365 IP addresses and URLs, fingerprints apps, and adjusts firewall and proxy configurations dynamically, so customers don’t need to keep tweaking their security controls reactively. With local Internet breakouts leveraging 100+ Zscaler DCs, local DNS and network peering with Microsoft across several sites, Zscaler customers get blazing fast performance with Office 365, with full visibility and control. Zscaler also added support for Microsoft tenant restrictions which enables customers to allow only business usage of Office 365 on their network. Read more here.