A Brief Analysis of the Effect of Firewall in Network Security

In 21st century,computers of all over the world will league together through the Internet,so the connotation of the information security has fundamentally changed.It not only has been changed from general defense to a very ordinary guard,but also has been changed from a kind of special field to a field that exists everywhere.In this dissertation,the classification and main feature of the firewall security technology will be expounded amply.