DNS Traffic Analysis: Issues of IPv6 and CDN

The Domain Name System (DNS) is a key naming system used in the Internet. Recently, the deployment of IPv6 and the DNS pre-fetch function in web browsers has significantly changed DNS usage. Furthermore, content delivery networks (CDNs) use complicated DNS configurations together with small TTL values to control their traffic. These three factors significantly increase DNS traffic. Thus, the importance of DNS traffic analysis has been increasing to properly maintain DNS operations. This paper presents an analysis of DNS full-resolver traffic at the University of Tsukuba in Japan. What we found are 1) The deployment of IPv6 has increased queries from clients as much as 41%, 2) The deployment of CDNs increases the use of small TTL values, the use of CNAME resource records and the use of out-of-bailiwick DNS server names. Since these increases are making the DNS cache hit rate low and the DNS response slow without recognition by Internet users, this paper seeks to warn application designers of potential system design risks in current Internet applications.