How to stop Win 10 accessing Internet but allow local access?

[LateJUnction]

When Win 10 support ends I plan to continue to use it, but I want to prevent Win 10 from accessing – or being accessed by – the internet, while allowing free access to my home network. I’m sure this is readily achievable; could somebody point me to a well respected how-to document designed to be used by non-networking non-experts?

 

[Grizzly]

I do not have a source available but you should be able to block internet access for that computer in your router.
I have a couple of devices that I do not want to access the WWW and I blocked them in a setting of my router. They still are able to access my local network though.
Might give you an idea.....

 

[ClippyBeer]

The easiest way would be to set a static IP address and set default gateway to 0.0.0.0

 

[Bighorn]

Late to the game but all I have to do is unplug the ISP's Modem from my Wireless Gigabit Router, doesn't affect my LAN.

 

[velvetviper]

To stop Windows 10 from accessing the internet while allowing local network access, follow these steps:

Disable Internet Gateway in Firewall:

1. Open Windows Defender Firewall → Advanced Settings
2. Go to Outbound Rules → New Rule
3. Select Custom → Apply to All Programs
4. Under Protocol and Ports, choose Any
5. In Scope, for "Remote IP," select These IP addresses → Add 0.0.0.0/0 (blocks internet but keeps local access)
6. Choose Block the Connection → Name it and Save

Disable Default Gateway in Network Settings:

1. Open Network and Sharing Center → Change adapter settings
2. Right-click your connection → Properties
3. Select Internet Protocol Version 4 (TCP/IPv4) → Properties
4. Click Advanced, remove the Default Gateway, and click OK