Comodo Firewall

Comodo Firewall Pro - Secure your system against internal attacks such as Trojan viruses / malicious software and external attacks by hackers.

Free Windows

Little Snitch

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

Commercial

TinyWall

TinyWall is a free software to harden and control the advanced firewall built into Windows Vista, Windows 7 and Windows 8.

Free Windows

Gufw

Gufw is an easy, intuitive way to manage your Linux firewall. It supports common tasks such as allowing or blocking pre-configured, common p2p, or individual ports port(s), and many others! Gufw is powered by Uncomplicated Firewall (ufw).

Free Open Source Linux

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

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

TripMode

Block internet connection for apps.

Commercial Mac OS X Windows

CacheGuard-OS

CacheGuard OS is an Appliance oriented Operating System dedicated to Web traffic Security and Optimization.

Free Open Source Windows VirtualBox VMware vSphere Hypervisor Microsoft Hyper-V Server Proxmox Virtual Environment

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