How to Ensure your PC is Not Connected to any Domains?

Just wondering if there's any way to make sure a Windows 10 PC isn't connected to any domains?

It might not be the correct definition but I'm including 'WORKGROUP' under that question.

Obviously I could disconnect the Ethernet cable but that's a little obvious.

What I mean is - to maintain as much control as is possible over a PC. That's while ensuring remote (network-based) access is either impossible or very, very difficult and easy to detect.

By calling a Workgroup a Domain, you are confusing the issue -- as they are very different.

If what you want, is NOT to be connected to any networks, be they Workgroups or Homegroups, then the simple solution is to disable all your networking hardware -- LAN and WLAN. That is the only way I know to make network-based access to your PC impossible.

For home networks, most routers include the option to do MacAddress filtering, which would prevent access by devices you have not already approved -- but InfoSec folks will tell you that is not iron clad, as MacAddresses can be spoofed.

In terms of detection, I run a consumer app known as SoftPerfect WiFi Guard which alerts me any time an IP is detected that I have not already noted and identified.

I am sure there must be more robust COMMERCIAL apps out there that you could buy that would do 24/7 monitoring of your network and the devices on it -- but I am not familiar with those and leave those recommendations to others.

Given I get very few real solutions (answers?) to my questions on these forums surely the right approach is one of elimination?

It just seems very likely that security experts will always sell the viewpoint that there's no such thing as an 'unhackable' network because there will always be liabilities, and their career is funded by vulnerable networks.

There must be a few very common methods of access, however. I don't ever seem to get even the most basic of leads beyond change passwords and what Google spews on the first page.

I appreciate you're trying to help, though.

If your behind a NAT router your ipcant be connected to via the internet unless something on you pc open it up. If your using wireless on the network most routers have a option user isolation which stops any wireless client from accessing local pcs

Disable the network adapters in the BIOS/UEFI and password-protect access. Note however that someone could plug in a USB-based network adapter (wifi or ethernet) so you would also have to manage the USB ports as well. If the device has Bluetooth then you would also need to disable this radio as well to prevent someone pairing it to a mobile device (like a phone) which has a wifi hotspot enabled. If it's a PC (rather than a laptop) then you would need to secure the case to prevent someone installing an internal wifi or ethernet adapter.