Little Snitch 50% off $34.95 = $17.48 Single License
Little Snitch 3 Overview [obdev.at]
Little Snitch informs you whenever a program attempts to establish an outgoing Internet connection. You can allow or deny these connections, or define rules to handle future attempts automatically. Little Snitch reliably prevents your private data from being sent out to the Internet without your knowledge.
Little Snitch protects your privacy!
As soon as you're connected to the Internet, applications can potentially send whatever information they want to wherever they want. Sometimes they do this for good reason, on your explicit request. But often they don't.
Little Snitch intercepts these unwanted connection attempts,
and lets you decide how to proceed.