Is it Windows 10 Pro or …?

With Windows 10 Pro you can disable Windows updates by editing group policy (run gpedit.msc with elevated permissions), look for Computer Configuration / Administrative Templates / Windows Components / Windows Update and set “Configure Automatic Updates” to Disabled.

Not sure how to do that on Windows 10 Home or other versions - the above probably corresponds to registry setting(s) but am not sure which one.

Hey, you might have trouble blocking windows 10 servers themselves, by IP or otherwise. I think it might be a lot more feasible to massgrave win 10 pro on your machine and disable updates by group policy.

I would use Use dns blocking.

…microsoft.com/…/what-are-the-ip-ranges-for-micro…

Remove all windows-machines, morelike.

For your use-case, you might want to block ALL the internet for that notebook, & then open ONLY the internet-link you require, for your test.

Trying to blacklist a dynamic-set of cloud IP-addresses seems like a losing-game.

Flip it: whitelist only what you explicitly require, for your test.

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Use Group Policy to disable updates.

If you have a Home version, disable the Windows Update service and the Windows Update Health service which prevents the Windows Update Service from being disabled.

Hkey_local_machine\system\CurrentControlSet\Services\WaaSMedicSvc

Change the Start value to 4 (disabled).

Now you can disable the Windows Update Service.

This is a Microsoft-provided solution to this question on their forums.