Today I noticed the following response from GMail after submission of email:
421-4.7.0 [x.x.x.x 15] Our system has detected that this message is 421-4.7.0 suspicious due to the nature of the content and/or the links within. 421-4.7.0 To best protect our users from spam, the message has been blocked. 421-4.7.0 Please visit 4.7.0 https://support.google.com/mail/answer/188131 for more information. f77si267316oig.47 - gsmtp Contrary to what 421 means generally ("try again later"), and contrary to GMail's own documentation page https://support.google.com/a/answer/3726730?hl=en where it says that 421 4.7.0 means "Try again later, closing connection" I find that trying again later always results in the same code, and it's therefore a permanent failure like 5xx would be. The particular email I saw in the logs was a newsletter from a publisher to an author, with links to new releases. Spammy in nature, maybe, but certainly solicited, and nothing really out of the ordinary. I noticed it only because our system saw the 421 code and dutifully kept requeuing for retry until the max number of attempts had been reached. Am I misunderstanding what 421 means after DATA or BDAT, or is GMail replying with the wrong code? Surely if it means to reject the email out of hand, it should say so, shouldn't it? We currently treat a 5xx reply after DATA or BDAT as a permanent failure, and don't retry. We treat 4xx replies after DATA or BDAT as temporary, and queue for retry. How should we handle it? Jeffry _______________________________________________ mailop mailing list [email protected] https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop
