DNS Performance : A study of free, public and popular DNS servers in 2019

Abstract: The Domain Name System (DNS) is an integral part of making the internet a more human-friendly place. However, it comes with the cost of an added abstraction layer that introduces extra latency in many aspects of the modern computing experience - a great selling point for many DNS services. In this thesis we look at the performance of DNS services and servers through the scope of 51 unique free, public and popular DNS servers. We use a specifically designed tool, DNSHoarder, to collect 714,000 datapoints of 250 different hostnames of varying popularity over seven days. From this data we find most DNS servers to exhibit a similar relative distribution of response times and performance differences between IPv4 and IPv6 to be minor or nonexistent. We also find network distance and quality to have a big effect on the performance of DNS as well as network latency to be a major limiting factor in further DNS performance improvements.