Char Jackson wrote:

Unless they've completely perverted the network stack in Win 10, which I
don't believe is the case, you can simply remove the default gateway from
your network settings, which will enable your Win 10 to remain on your local
LAN while preventing any off-LAN traffic, in or out. To me, that's a lot
easier than pulling the cable and/or reverting to sneakernet.

I don't know how the P2P windows update works, it might need to discover
the updates direct from the Microsoft, and use any local peers as a
download source, or it might discover updates fro local peers too...