I've tried various apps, including this. Other apps like this too, both on Linux and Windows.
On Linux, OpenSnitch and Douane. OpenSnitch is not optimized and results in high CPU usage when you move a lot of traffic. With Douane I had trouble using it for longer than a day since it resulted in my PC crashing caused by the kernel module that it installs. There seemed to be a bug in the C code somewhere, and it didn't go away when I checked back a couple months later.
Coming to Windows, most apps were really old. Only some actually worked with Windows 10 where NDIS 6.x came in and broke some things. Those that did work were so basic you could just use the Windows Firewall app. I tried everything I could get my hands on (in a VM) in search of the nice features that LittleSnitch provided. GlassWire was so far ahead in the features and control it provided, I made an exception in buying a subscription based software (which I almost never do)
On Linux, OpenSnitch and Douane. OpenSnitch is not optimized and results in high CPU usage when you move a lot of traffic. With Douane I had trouble using it for longer than a day since it resulted in my PC crashing caused by the kernel module that it installs. There seemed to be a bug in the C code somewhere, and it didn't go away when I checked back a couple months later.
Coming to Windows, most apps were really old. Only some actually worked with Windows 10 where NDIS 6.x came in and broke some things. Those that did work were so basic you could just use the Windows Firewall app. I tried everything I could get my hands on (in a VM) in search of the nice features that LittleSnitch provided. GlassWire was so far ahead in the features and control it provided, I made an exception in buying a subscription based software (which I almost never do)