Meta ignores RFC 2920; ZuckMail can't send mail to servers running OpenSMTPD

Meta ignores RFC 2920; ZuckMail can't send mail to servers running OpenSMTPD(marc.info)

35 points by pghatedphones 1 year ago | 9 comments

tedunangst 1 year ago |

Not supporting pipelining is a somewhat effective low effort spam filter. Spammers don't have time to wait for response codes, just blast the message and move on to the next sucker.

AnotherGoodName 1 year ago |

Above thread created 2 days ago but also isn’t this a broader bug? I was getting no emails on gmail either fwiw (wanted a recovery code, never got the email).

Let’s just wait and see for this one. I do not think it’s OpenSMTPD specific. The reply there is not from Meta, its from OpenSMTPD saying the bug is on Metas side. Which i think is true. I think they might have a major issue which has nothing to do with OpenSMTPD, Metas mail servers are just failing all round.

Bender 1 year ago | |

Indeed it appears to be a long running broader bug [1] of 7 years. Perhaps someone could increase log and header verbosity or enable some form of debugging to see what behavior WhatsApp is invoking. It appears this [2] is how to enable debugging in OpenSMTPD. Once enabled one could trigger an email through WhatsApp to see specifically what it doing. I am nosy and curious enough that I hope someone posts the debug output here after sensitive stuff is redacted. I do not have a WhatsApp account.

[1] - https://unix.stackexchange.com/questions/392729/opensmtpd-pi...

[2] - https://wiki.archlinux.org/title/OpenSMTPD#Subsystem_tracing

JdeBP 1 year ago | | |

I'll see your 7 and raise you 10.

* https://github.com/OpenSMTPD/OpenSMTPD/issues/451

semiquaver 1 year ago | | |

There’s no evidence it’s a bug in opensmtpd, rather it’s that other SMTP clients such as WhatsApp’s mail servers are assuming support for the (non-mandatory) PIPELINING extension instead of respecting the EHLO-advertised (lack of) support.

eqvinox 1 year ago |

exim, if configured to do so (which is a reasonable initial spam barrier), will also reject mails due to this behaviour. It's sufficiently common (for spam) that I filtered it from logs to avoid junk buildup.