Measuring the Consolidation of DNS and Web Hosting Providers

TL;DR

The paper investigates growing Internet consolidation by quantifying how DNS and web hosting are concentrated among a small set of providers for popular domains. Using the Tranco top 10K and data collected from six global vantage points, it measures the autonomous systems and organizations hosting authoritative name servers, domain index pages, and external resources, revealing that $60 ext{ extperthensymbol}$ of index pages and external resources are hosted by five providers (Cloudflare, Amazon, Akamai, Fastly, Google). The authors introduce concrete metrics (unreachable and affected) to assess resilience under provider outages and highlight global consistency in these trends. They also discuss implications for resilience, censorship, and policy, and release their data and methodology to enable ongoing, standardized monitoring of consolidation. Overall, the work provides a rigorous cross-provider, cross-vantage-point view of DNS and web hosting concentration and its potential impact on Internet stability and governance.

Abstract

Despite the Internet's continued growth, it increasingly depends on a small set of service providers to support Domain Name System (DNS) and web content hosting. This trend poses many potential threats including susceptibility to outages, failures, and potential censorship by providers. This paper aims to quantify consolidation in terms of popular domains' reliance on a small set of organizations for both DNS and web hosting. We highlight the extent to which a set of relatively few platforms host the authoritative name servers and web content for the top million websites. Our results show that both DNS and web hosting are concentrated, with Cloudflare and Amazon hosting over $30\%$ of the domains for both services. With the addition of Akamai, Fastly, and Google, these five organizations host $60\%$ of index pages in the Tranco top 10K, as well as the majority of external page resources. These trends are consistent across six different global vantage points, indicating that consolidation is happening globally and popular organizations can influence users' online experience across the world.

Figures (16)

• Figure 1: The measurement pipeline used to study each domain.
• Figure 2: Number of domains that use exclusively one AS to host their name servers (unreachable) and use that AS at least partially (affected).
• Figure 3: Percentage of domains that use exclusively one AS organization to host their name servers (unreachable).
• Figure 4: Percentage of domains that use exclusively one AS to host their name servers (unreachable).
• Figure 5: Percentage of domains that use exclusively one AS organization to host their index page (unreachable).