Size: 600KB
Look 'n' Stop Lite is a free Windows firewall that filters inbound and outbound traffic from your computer.
*Note that this is a 30 day free trial.
Size: 7.43MB
Kerio Personal Firewall (KPF) helps users control how their computers exchange data with other computers on the Internet or local network.
Size: 3MB
Jetico Personal Firewall software provides you with security against hackers who try to access your PC when you are connected to the Internet. Having inherited the Open architecture principles from BestCrypt, the Jetico Personal Firewall allows you to construct a strong yet accurate security policy and provides clear control over your network connections.
Size: 3.1MB
A Windows 98/ME/NT/2000/XP firewall that has network packet filters, network events filters (that allows you to block application level events) and process activity filters (that hopefully blocks application hijacking attempts where a trojan uses your browser to send information to the internet). Please read here before installing.
Size: 1MB
Guarddog is a firewall configuration utility for Linux iptables. It also lets you maintain and modify the firewall in place. It uses a "what is not explicitly allowed, is denied" philosophy. The software is released under the GNU GPL.