In this series of articles I will expose the weaknesses that are often ignored. Firewalls are better than nothing most of the time. I hope I am being clear enough. If you still think I am advocating the removal of firewalls, stop reading now and please do not email me. Then the Internet expanded at a furious rate and all sorts of people become connected, many of whom have hostile intentions.
Firewalls are good at many things, and also very poor at others.
Firewalls are very useful for implementing security measures and, to some degree, usage policies on your network. Because you can force all network traffic destined for external networks to pass through a firewall, you can also apply rules on what is and isn't allowed. After World War I France was understandably nervous about another German invasion, so they built a string of fortified bunkers and defenses along their border with Germany. The Maginot Line was extremely effective in its immediate purpose of preventing the Germans from getting through, but it failed in the larger sense of being a security measure. The Germans simply went around it, bypassing all the expensive fortifications and dug-in troops, and punching through the Ardennes.