Comparing DNS Resolvers in the Wild
The Domain Name System (DNS) is a fundamental building block of the Internet. Today, the performance of more and more applications depend not only on the responsiveness of DNS, but also the exact answer returned by the queried DNS resolver, e. g., for Content Distribution Networks (CDN). In this paper, the authors compare local DNS resolvers against GoogleDNS and OpenDNS for a large set of vantage points. Their end-host measurements inside 50 commercial ISPs re-veal that two aspects have a significant impact on responsiveness: the latency to the DNS resolver, the content of the DNS cache when the query is issued. They also observe significant diversity, even at the AS-level, among the answers provided by the studied DNS resolvers.