How useful is it to prevent Linux applications from setting up any untrusted connections, and can it be done easily?

Threat: your Linux machine gets compromised in some way (untrusted app, or compromised install package or update, or an app is compromised because of a vulnerability, etc.) and something on your system tries to “call home”. S… Continue reading How useful is it to prevent Linux applications from setting up any untrusted connections, and can it be done easily?