中文摘要：

为解决因国外根/顶级域名系统无法提供域名解析服务而影响我国互联网正常运行的问题,设计并实现了一种高效的DNS信息获取及备份恢复系统。通过被动获取DNS数据包与主动发送DNS请求相结合的方式,可获取网络中活跃的域名信息。利用基于可变长请求队列的发送速度自适应方法来有效控制请求效率,以适应网络带宽和DNS服务器负载。详细介绍了整个系统的设计和实现,并进行了性能测试与分析。该系统对建设国家根/顶级域名备份恢复系统具有重要参考价值。

英文摘要：

The Internet in China will not work normally when the root/ top-level domain name systems don＇t provide domain name resolution services.To address this problem,the paper designed and implemented an efficient backup and recovery system to obtain DNS information.Through a combination approach of the passive access to DNS packets and the active access to sent DNS requests,the information of active domain names in Internet could be gotton.In order to adapt to network bandwidth and DNS server load,used an adaptive methods of sending rate based on variable-length request queue to effectively control the efficiency of request.This paper described the design and implementation of the entire system.The performance testing and analysis of this system was also carried.This system has high reference value to building national root / top-level domain name backup and recovery system.