As of two weeks ago I'm now on Android from Windows 10 Mobile. Wow, what a change. Really hating just about everything. I'm finally getting things configured as I want and am trying to keep as many MS services as possible.
What I've discovered today is that after I set up Outlook IMAP for my work email, it's connecting to my server via 188.8.131.52(a Microsoft server), NOT directly from my device.
At this moment, I'm 192.168.1.3 on my WLAN and 184.108.40.206 mobile data. I just watched 220.127.116.11 connect to my mail server and new mail notification pop up on my phone.
I'm two seconds away from uninstalling Outlook and seriously reconsidering my commitment to MS. There's -zero- reason for my information to route through a secondary server.