Two Providers, a Stubborn Plateau, and a Very Long Tail: Email in the Tranco Top 1M

Abstract

This study examines ten years of changes in email infrastructure across the Tranco Top 1M using large-scale DNS measurements. It analyzes the evolution of self-hosted email, Google Workspace, Microsoft 365, the long tail of MX providers, and the adoption and enforcement characteristics of SPF, DKIM, and DMARC. The research was originally published on RIPE Labs. An accompanying public Email Infrastructure Statistics project provides access to the measurements and interactive visualizations. The study focuses on long-term structural changes in email infrastructure, including increasing provider concentration and the decline of self-hosted email.