TinyWall has been designed to improve the default firewall of Windows. TinyWall lets you work while protecting you. There are no annoying popups but configuration is very simple. Using the advanced Windows Firewall built into newer Windows versions, TinyWall's performance impact is negligible. No drivers or kernel-components are installed so it does not influence system stability. Automatic learning, blocklists, password lock, firewall tampering protection and built-in tight firewall rules help increase TinyWall's and your computer's security even further. Firewall modes and lots of other convenience features make TinyWall extremely easy to use for anybody. All packed into a download that is about a megabyte.
Thanks to rushdie for the update.