How i cut internet connection of programs

[Ademcan]

I want to block programs from accessing the internet in Windows. I dont know what they doing with internet but my computer getting very tired. They also adding itself to startup on pc. Actually i want to write a manager program with options like open, pause... Which program used how much bandwidth and for seeing list them all. My problem for windows but i also wondering how can be with linux.

[helios]

Just use the firewall. By default the firewall is set to allow outgoing connections, but you can change that to block by default and add rules to explicitly list which programs you want to allow to connect outside.

[Ademcan]

I will write an application myself with C++. I asking in order to learn, not for use already existing programs

[Ganado]

Have no idea of the quality if this, but for Win32 API functionality to programmatically change the firewall, check out: https://docs.microsoft.com/en-us/previous-versions//aa364726(v=vs.85)

On Linux I've used ufw and iptables... Since all those utilities are presumably open-source, you could try exploring them.