Little Snitch

Little Snitch is a firewall application that monitors and controls outbound internet traffic.

Commercial

ZoneAlarm Free Firewall

ZoneAlarm Free Firewall blocks hackers from infiltrating your home PC by hiding your computer from unsolicited network traffic.

Freemium Windows

Radio Silence

Radio Silence lets you block individual apps from accessing the internet. It never throws pop-ups on the screen, and is completely invisible.

Commercial Mac OS X

Hands Off!

Hands Off! is an application to monitor and control the access of applications to your network and disks.

Commercial Mac OS X

Private Eye

See connections in real-time: When an app makes a network connection, you see it instantly on your screen. There's no delay and you don't have to use a separate recording mode.

Free Mac OS X

IceFloor

IceFloor is the first OS X free graphic frontend for PF. Configure the PF firewall in a few clicks using a very simple interface and a step by step in-app configuration guide (Quick Start).

Free Open Source Mac OS X

Flying Buttress

As Apple's built-in Firewall preferences improves in both functionality and security, I will be aiming Flying Buttress more at users who need the advanced firewall...

Free Mac OS X