When I connect both directly over ethernet to the MiLAN I get:
macOS: valid IPv4 and IPv6
Win10: IPv6 only (funny, isn't it?)
I'm using the DIR-850L B1 for Wi-Fi and as a router for my printer as well as my IP-phone. I might try turning the DIR into a switch, but I'm not sure, if my printer will work. On Win10 I'll have to fix the missing IPv4, when connected directly to the MiLAN …
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The phone and the printer are still IPv4-only devices.