| 1. | In the view of the analysis of vulnerability , a deep , multi - level , all - round defense system model was proposed . the model , aiming at enhancing the survivability of dns , exerted the technology of fault tolerance and intrusion tolerance 该模型以增强dns系统可生存性为目标,以容错和容侵为基础,构建出一个纵深、多层次、全方位的防御体系。 |