As the technology of network developing fast, the problem of network security is emerging day by day. In order to temporize this trend, different kinds of network safety methods appear, such as Virus Detecting, Code Technology, id Authentication, etc. Even though, incalculable economic loss are caused because many servers are attacked without effective detecting and defending.
DoS（Denial of Service）Attack, The frequency and complexity of these attacks are increasing, intrusion detection technologies have got much focus in academic and industry in recent years. DoS attack is regarded as one of the biggest challenges of Internet. The researches on these subjects are of great theoretic and practical significance.
It becomes necessary to do kinds of configurations and inspect the running status for fully playing the performance of Network Firewall. Such as setting ip address, filter rules, protected hosts and inspecting flows, types of attacking, system logs and so on. Under this situation, it will great improve the defense ability of firewall, as long as you choose a proper control strategy.
Keywords Network Security；Denial of Service Attack；Network Firewall
