> This shows part of the downside of consolidating email into a handful of massive providers.
Kinda yes, kinda no. It seems the more relevant quantity is the software that is running (e.g. Cisco, Postfix, etc), rather than who hosts it. Even in a world where email was far more decentralized, this would still be a problem, perhaps even more so as there'd be a much longer tail for mail systems to be updated.
There’d be less domains to spoof per server with SPF spread across more IPs. However you’re right about the long tail and since the best value is likely internal spoofing (ie: ceo scam), there’s upside to the huge providers just dealing with it for everyone.
Kinda yes, kinda no. It seems the more relevant quantity is the software that is running (e.g. Cisco, Postfix, etc), rather than who hosts it. Even in a world where email was far more decentralized, this would still be a problem, perhaps even more so as there'd be a much longer tail for mail systems to be updated.