On the Consolidation of the Internet Domain Name System

Several parts of society have expressed rising alarm about the Internet's consolidation in recent years. One of the critical concerns raised by this trend toward consolidation of infrastructure, traffic, users, and services is the concentration of many essential Internet resources among a small number of providers. Some consequences of such consolidation (single points of failure) were exposed in 2016 and 2019 in large-scale Distributed Denial of Service (DDoS) attacks on two DNS providers. In this paper, we study the Domain Name System (DNS) industry's consolidation in light of multiple country-code Top-Level Domains (ccTLDs) and generic top-level domains (gTLDs) by resolving and evaluating the authoritative name-servers (NS) for all domains in each TLD during five years. We show that, the Top 5 DNS providers account for more than 20% of all domains and, more shockingly, the Top 100 providers account for about 80% of the entire examined IPv4 domain namespace. We also reveal that domains in certain TLDs are highly concentrated in the hands of a few providers. For example, Estonia's (.ee) Top 5 providers will hold around 78% of the total TLD namespace in 2021. Additionally, we examine the domain concentration per TLD in terms of provider location origin. We notice a strong presence of local companies in Europe's top-level domains, emphasizing the Russian Federation.