Since Microsoft has released Windows 10, many things have changed. Notably, you are now almost forced to upgrade your old Windows session (Win7, Win 8 and 8.1). Also, Microsoft now collects a complete set of data - and they call that telemetry and data analysis for cortana. Only, for that to work, all the data needs to be collected all the time, as eventually you can tell cortana to execute an action. Imagine the Microphone always active and listening sending the data out to Microsofts systems for analysis. I don't know. This is nothing I want to live in.

Various articles have emerged with a little analysis on what Windows 10 is doing.
See for yourself: Localghost, arstechnica, HowtoGeek etc.
Checking the data behind that, I came to the conclusion that there are 59 IPv4 Addresses data is sent to, and 6 IPv6 IP addresses. This - is bad. Because of that I have decided to implement a dedicated Anti-Microsoft rule that blocks all traffic from within this LAN towards any of these IP Addresses.

If it was only Windows 10 that was doing that, we could stop here. But there are rumors that the telemetry and data collection is also backported to Windows 7, Win 8 and 8.1 as reported here: https://freedomhacker.net/latest-windows-7-8-81-update-spy-windows-10-4568/
That - is a bummer... there is nothing the regular user can do against. Only we admins can protect our users from being eavesdropped at all times...

For convenience - whoever wants the block-list, here is an export of my database based list: Microsoft_Win10_Blocklist.csv

Update: I was sent a link which provides a Batch file to remove the updates Microsoft sends to the Win7/8.x systems to replicate Win 10 behavior. Find it here: Remove telemetry updates for Windows 7 and 8.1