When someone I know asks me what applications I recommend always having on a Mac I always use Little Snitch in the package, and it is that an application that allows us to decide on absolutely every connection that leaves and enters the Mac gives an impressive security bonus.
Even better
With version 3.1 come several novelties, but I am going to focus on the one that seems to me the most interesting and the one that precisely makes the jump from 3.0 to 3.1: the automatic switching between profiles.
Thanks to this novelty, we can configure different actions in the firewall so that they are activated or not depending on the network to which we are connected. That is, if for example we go to work we may be interested block all the connections that come out of a certain server, but when we get home we want to let them pass because we have decided to do so. This is now done automatically, and I have the impression that for many it will be a real wonder.
The update brings some small news more in the sense of correcting bugs and optimizing operation, but none that deserves as much attention as the one we have discussed more extensively in this post.
Note: Little Snitch is an application for advanced users. For normal use, the free OS X firewall is more than enough.
More information - Little Snitch 3 reduced to half its regular price