Microsoft Express Routes woes...

This is classic.......

We have a direct BGP peering session to Microsoft using Express Routes for
the public peering session for services like Email, one drive, etc. this
uses MS Public. We also have/use MS Azure Public as well as MS Azure
Private in place for a few years now. We have had this happen a few times
already where one team at MS makes a routing change, and the other team is
either not aware of the change, or else doesn't communicate the change

So late last night, while a change was being made to a completely different
area of our network, they asked that I back out my change due to our entire
organization not being able to access share-point online, or MS One drive.

I had zero evidence it was our change. further investigation on our border
routers, revealed all four (4) of our ISP's were advertising the MS block
as a /24 prefix:

Hi Craig,

Microsoft apologizes for your routing issue. Our Wide Area Networking and
Express Route teams were already aware of this issue from your ticket. I
have communicated with their leadership, and they are working on a fix for

Please feel free to contact me at if you would
like to follow up off list.


Ingrid Erkman

Director of Interconnection