On Wed, 15 Oct 2008, Stuart D. Gathman wrote:
But they are the overseas partner of my customer, and their mail
has to go through - but I still have to block all the other garbage. This
level of filtering is inherently custom.
Still, replacing public blacklists with custom ones isn't necessarily an
improvement. A public blacklist can be effective with a shorter expiry
time than a private one, which means it is less likely to FP when IP
addresses change ownership.
It's better to use public blacklists, but maintain a private whitelist to
override if necessary.
You could set your system up to automatically whitelist any address your
customer mails to. This will protect you if someone your customer is
already talking to suddenly gets listed.
One other thing -- you mentioned the "evolved" spammers are evading your
content-filtering by sending images. A simple no-binary-attachments
content filter would stop those cold. That's too harsh for most sites,
let alone your FP-phobic environment, but if it was only applied to
never-seen-before domains, it might work.
---- Michael Deutschmann <michael(_at_)talamasca(_dot_)ocis(_dot_)net>
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