Examining the Centralization of Email Industry: A Landscape Analysis for IPv4 and IPv6.

Centralization of key Internet services, including email, can result in privacy and security concerns and increase the number of single points of failure. This paper measures and analyzes a large-scale dataset of email providers gathered from MX records of top-level domains. The findings reveal the concentration of email infrastructure providers for each TLD and identify the most significant providers in the market. The paper also demonstrates that the IPv6 adoption increased the centralization of email servers. The research contributes to the state-of-the-art by thoroughly examining email infrastructure centralization and identifying potential areas for future research.