You miss a key point, his router is allocating these devices local IPs over his routers DHCP.As maybe but does this happen when the machine running Win 10 is switched off and using a device running Android, iOS or Linux to look at the router or perhaps an older version of Windows such as Win 7. I feel the OP needs to eliminate the possibility of this being a Win 10 induced phenomenon.
I donít understand how it could be? Are you suggesting Windows 10 is allowing a bunch of neighbour devices onto the network including additional windows devices, mobiles etc?
It simply doesnít work like that... The router only allocates IP addresses to devices connected via Ethernet or WiFi, thereís no magic that causes windows 10 to provide neighbouring devices access to the network.
Provide me a link to a valid source that shows having windows 10 allows unknown devices onto a local network. Then provide me a source that explains how nmap is finding open ports on an IP address youíre saying is down to Windows 10?
Running Windows 10, or any device for that matter, does not provide other devices access to the local area network, with valid IP addresses and open ports. Thatís a huge gaping security hole and simply is not the case.. if you can find me a source anywhere that says it does all of this I will be amazed.
Imagine a data centre running Windows OS, say itís the server processing payment card information. Are we now to believe if itís windows 10 itís going to just let foreign devices hop onto the network? What about the latest point of sales used in stores on Windows 10, Iíve seen a couple using WiFi, the same WiFi used by in store iPads and tablets which process mobile payments.
Are these letting in every walking by customer into the wireless, so they can be on the same network environment as cardholder data?
Iím sure this is how Microsoft designed the OS. Come on...
End of story, Windows 10 does not allow unknown devices onto the LAN. It can share the WiFi password but thatís a different system, it does sometimes show a bunch of extra devices in the OS GUI, none have an IP locally.