John Heidemann

Recursives in the Wild: Engineering Authoritative DNS Servers

TitleRecursives in the Wild: Engineering Authoritative DNS Servers
Publication TypeTechnical Report
Year of Publication2017
AuthorsM. Müller, G. C. M. Moura, R. O. de Schmidt, and J. Heidemann
Date Publishedjun

In Internet Domain Name System (DNS), services operate \emphauthoritative name servers that individuals query through \emphrecursive resolvers. Operators strive to provide reliability by operating multiple name servers (NS), each on a separate IP address, and by using IP anycast to allow NSes to provide service from many physical locations. To meet their goals of minimizing latency and balancing load across NSes and anycast, operators need to know how recursive resolvers select an NS, and how that interacts with their NS deployments. Prior work has shown some recursives search for low latency, while others pick an NS at random or round robin, but did not examine how prevalent each choice was. This paper provides the first analysis of how recursives select between name servers in the wild, and from that we provide guidance to name server operators to reach their goals. We conclude that all NSes need to be equally strong and therefore we recommend to deploy IP anycast at every single authoritative.