One feature common to many Windows firewall programs is not only the network port filter but the ability to monitor and approve programs attempting to communicate to the Internet. For you Mac users out there looking a program to do this, check out Little Snitch.

Little Snitch is not a firewall, as this is what it does:

Little Snitch informs you whenever a program attempts to establish an outgoing Internet connection. You can then choose to allow or deny this connection, or define a rule how to handle similar, future connection attempts. This reliably prevents private data from being sent out without your knowledge. Little Snitch runs inconspicuously in the background and it can also detect network related activity of viruses, trojans and other malware.

This program is ideal for preventing any ’suspect’ network activity as you can completely block it from leaving your computer. Little Snitch is shareware but is probably worth the price for the security conscience Mac user out there.