I really cannot believe they did not immediately hack in a new rule to their SMTP server: never return a 5xx (permanent failure), instead return a 421 (temporary failure try again later).
That simple fix buys them 24-72 hours to solve this properly.
Yeah, it burdens servers sending mail to them because now they have to hold on to all mail (including mail that really is permanently undeliverable) for another day or so, but that's still better than what's happening right now.
That simple fix buys them 24-72 hours to solve this properly.
Yeah, it burdens servers sending mail to them because now they have to hold on to all mail (including mail that really is permanently undeliverable) for another day or so, but that's still better than what's happening right now.