Mac users are increasingly using software firewalls to prevent apps from making outgoing connections. Here are some tips, and links to help you build whitelists.
ports
How can I best use the two Ethernet ports on my Mac Pro?
So you want to hook up your Mac to an external display or projector. That should be a simple task, but are those ports DVI, Mini DisplayPort, HDMI, or what?
There are techniques allowing you to leave firewall ports open, or for opening up ports from outside, whilst retaining security.
Out with USB 2 and in with USB 3; out with FireWire and in with Thunderbolt, then Thunderbolt 2. But which should you choose to use, and how?
For most, our firewall is the most robust protection between us and the Internet. But it is not just a case of set and forget.
The Eclectic Light Company 