On 2015-09-28 14:32, Joe Quinn wrote:
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.
out of curiosity, i decided to grep my inbox for e-mails without any
message-id: header. i found 37 e-mails without a message-id out of a
total of 1144.
29 - domain {renewal|transfer}-related e-mails all from godaddy
5 - spam
2 - receipts from apple retail stores
1 - newsletter from the local credit union
it would have been a major inconvenience if these 37 messages had been
marked as spam (well, the domain-related e-mails and receipts, at
least).
i should note, however, that each of these 37 e-mails matched the
MISSING_MID rule with a score of 0.14.
on a related note, i sometimes receive messages missing the Date: header
(which *is* required by rfc5322). several months ago, i began testing
scoring/blocking them only to discover that level3.com (one of my
upstream transit providers) was sending out some rather important
notification e-mails without a Date: header. even though they were in
violation of rfc, i still couldn't do anything about it because i needed
to receive those notices.
also, out of those 1144 e-mails currently in my inbox, seven (all
receipts from atlantic.net's billing system) contain two Date: headers.
based on just what i've found in the last 10 minutes, i would be very
careful about scoring anything related to {invalid|missing|extra}
headers too high. definitely test your rules extensively (with very low
scores) before rolling them out to production!
/chl
