Valdis Klētnieks wrote on 15/12/2019 23:31:
The point is that, given a syntactically correct and acceptable EHLO, there's a massive difference between: mail.ietf.org says "550 5.7.1 mail rejected due to EHLO violating local policy" mail.ietf.org says "550 5.7.1 mail rejected due to EHLO RFC2821 violation".
there's no requirement for the text from a 550 reply code to be parsed by the MTA, so the difference is in the eye of the person receiving the bounce message. If it's semantically inaccurate, then maybe someone can change the text and we can move on?
Nick
