DNS Measurements at the .CN TLD Servers

The domain name system (DNS) is a fundamental Internet´s infrastructure. There have been several studies on DNS measurements such as server workload and deployment characteristics. In this paper, based on the traffic collection spanning a two days period, we present a detailed study of the key characteristics of the .CN top level domain (TLD) name servers which are located at eight different sites. Results demonstrate that properties of these geographically distributed servers vary a lot in terms of traffic load, client population as well as their temporal and spatial patterns. As the country code TLD (ccTLD) for China, only 9% of clients are from domestic, which contribute to nearly 50% of all queries received by these servers. Besides, the validity of queries is also evaluated, which turn out to be better than that of the root servers.