TekSavvy → Re: Do I need a firewall being behind a router?

People get obsessed by the highly ineffective vectors like supplemental firewalls to replace the ones they already have, and completely miss far more dangerous vectors... You really have more important things to be worrying about than this.

My point is, a focus on security should be spent where it will be useful, not on trivial stuff like this.

Mac users have the OS X firewall
»support.apple.com/kb/PH4275

and an app like Little Snitch is a good companion to that
»www.obdev.at/products/li ··· dex.html

ALWAYS enable the Apple firewall if you are roaming on unsecure networks, ie. hotels, Starbucks, car dealerships while waiting for your car, airports, conventions, etc....