If you ignore hard bounces on the Hotmail infrastructure...' There will come a day, possibly sooner than you'd like, when the system will blacklist you, and you'll find it hard to get mitigated.
All automatic. Aloha, Michael. -- Michael J Wise Microsoft Corporation| Spam Analysis "Your Spam Specimen Has Been Processed." Got the Junk Mail Reporting Tool ? -----Original Message----- From: mailop <[email protected]> On Behalf Of Bill Cole Sent: Wednesday, February 27, 2019 10:25 AM To: [email protected] Subject: Re: [mailop] deactivation of hard bounces On 27 Feb 2019, at 12:36, Michael Peddemors wrote: > On 2019-02-27 9:27 a.m., Bill Cole wrote: >> However, there are specific basic and enhanced SMTP reply codes which >> are direct explicit statements that an address is non-existent which >> should be honored immediately rather than taken as possibly mistaken >> and retested later with a different message. For example, a 550 reply >> to RCPT (or either stage of DATA, if there's only one accepted RCPT) >> without any enhanced status code should ALWAYS be treated as an >> indication of a non-existent address, as should 550 followed by any >> 5.1.x enhanced status code. > > Hi Bill, > > Do remember, in spite of RFC's there also is the perspective by many > SMTP implementations or operators, to NOT reveal whether an email > address actually exists, vs whether the message is non-deliverable. > > Some implementations 'choose' to obfuscate the result to some extent > to help against dictionary attacks.. Which is a fine rationale for dropping addresses that chronically hard fail in any way after a very small number of those hard failures which may or may not indicate address non-existence (which I believe I did advise.) > Something to consider.. Perhaps, but not really very relevant to what I said. If the receiving system explicitly says that an address is non-existent, a sender should believe them without re-testing. If they are explicitly asserting address non-existence when the real cause of rejection is the sender or the content, they are still telling the sender to stop mailing that address and that request should be honored. If you act otherwise, you can (rightly) damage your own reputation. For example, I have used dead addresses (which have been kicking back '550 5.1.1' replies to RCPT for extended periods, sometimes forever) as spammer canaries. The same unfamiliar sender hitting one twice in a short enough time will not be sending anything to any address on the same mail system for longer than the average ESP lifetime, absent manual intervention. This has been an effective and low-risk tactic for years. -- Bill Cole [email protected] or [email protected] (AKA @grumpybozo and many *@billmail.scconsult.com addresses) Available For Hire: https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Flinkedin.com%2Fin%2Fbillcole&data=02%7C01%7Cmichael.wise%40microsoft.com%7C168feff578174dc2b8eb08d69ce1b5f0%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636868890575941249&sdata=QPC2u3Vi%2Bfr9l9GV%2Fd%2BOUL%2BzwddD3pF0RrG3wcuJmLU%3D&reserved=0 _______________________________________________ mailop mailing list [email protected] https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fchilli.nosignal.org%2Fcgi-bin%2Fmailman%2Flistinfo%2Fmailop&data=02%7C01%7Cmichael.wise%40microsoft.com%7C168feff578174dc2b8eb08d69ce1b5f0%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636868890575941249&sdata=4gMOX90tl%2BddHcMCduiYhhR%2BR8DMsEH6Bhm1nGbzVV0%3D&reserved=0 _______________________________________________ mailop mailing list [email protected] https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop
