For defending denial of service attack and ports scanning, we adopt corresponding measures in network layer and transport layer.
对于防御拒绝服务攻击与端口扫描，我们在网络层与传输层分别采取相应的措施进行防范。
2
Attack An attempt to circumvent the security measures in place on a network either to gain unauthorized access to the system or to force a denial of service.
试图破解网络上某一处的安全防护措施，以便在未获得授权的情况下访问系统或者是遭到服务拒绝。
3
This paper introduces the implications, phenomena, and methods of the attack of the service denial on the Internet, and offers a few preventive measures.