On 9/28/2015 2:22 PM, Philip Prindeville wrote:
Though listed as optional in the table in section 3.6, every message
SHOULD have a "Message-ID:" field. Furthermore, reply messages
SHOULD have "In-Reply-To:" and "References:" fields as appropriate
and as described below.
This is much more plain-english and clearly says SHOULD, so my
interpretation of the rest would be what MUST be done IF "Message-ID" is
present. In any event, RFC compliance is orthogonal to being spam or ham
and at the end of the day, SA is an "I don't want this email" spam
classifier and not an RFC validator.
If you don't want to be getting those emails, they are spam and you
should score it something reasonable that doesn't prevent you getting
other desired messages. While I don't have any specific examples of ham
without Message-ID, it's not a stretch to imagine they exist. I
personally wouldn't write that rule.
