Firewalls - how do they work?
As I am in incredibly smart person, I found myself wondering about firewalls. And I said to myself, the only thing they really seem to do is block all connections to ports (maybe only the first 1024 anyway). So I wondered, could I make a program that binds to all those ports in the same way, and only 'opens' (doesnt bind to) the ports I specify to be open? If I did that, would it be considered a firewall? I'd like any suggestions and comments on this matter, I'm about to download a free one now and see if thats all it does, and if it is I'll make my own program to do it :)