On Fri, 26 Jun 2009, John Rudd wrote:
It sounds like Charles' user base and cost/benefit analysis is
different, and that's fine.
Actually no, it's not. I arrive at the same cost/benefit analysis and have
instituted the same general policy - I block all hosts on PBL. Thought I
made that part clear.
But my point here is: legitimate isn't just something that varies from
mail-admin to mail-admin, and user to user, it's also a difference in
whether you're talking about messages vs submitting hosts. Blocking a
host as being illegitimate doesn't mean "it submits 0 legitimate
messages". It means it doesn't submit enough legitimate messages to
justify the number of illegitimate messages it is sending (or is likely
to send, based upon whatever reputation/policy got it black listed).
(Charles nods enthusiastically) Exactly. It's the distinction between
whether a filter to block all references to a specific brand of drug
blocks a medical discussion about the drug. The filter has enforced the
policy perfectly, but the *intent* to only block drug *ads* has led to
a false positive. Likewise, the intent to block spammers by marking
their hosts as illegitimate also blocks legitimate senders who have ended
up in the IP block where they "don't legitimatey belong". They are not in
a legitimate place, but that doesn't stop them from *trying* to send
legitimate messages. Thanks John!
- C
