Where the Fortune 500 Actually Live: The DNS, Mail, and CDN Stack Behind America's Biggest Companies
We resolved the full DNS, MX, web-edge, and email-authentication stack of 500 Fortune 500 corporate domains against a May 2026 typed crawl. No single vendor owns enterprise DNS — 28% of the F500 still run their own. Proofpoint sits in front of 48% of mail-enabled inboxes. Akamai serves a third of the web edge. And the F500 enforce DMARC at 73% versus ~42% globally — yet MTA-STS reaches just 2.3%. This is the corporate Internet's plumbing, measured from the records themselves.