> We've got exim putting a warning header on mail coming from any
> ORBS-flagged domains. A *lot* of legitimate stuff ends up with that header.
> I'd be very wary about out-and-out rejecting stuff. (aside: doesn't ORBS
> have a bit of a rep for being nutso about listing domains at the drop of a
> hat?)
ORBS does not list domains. They list *IPs* for exactly two reasons:
o They can verify the IP to be an open relay
o There are known open relays, but the network blocks the ORBS tester
That's a very clear technically oriented manner. Quite unlike MAPS,
who recently listed ORBS and accused them of spamming, obviously because
above.net insists on running open relays and blocking the ORBS tester,
hence ending up on the ORBS list.
ORBS is not only for filters. ORBS helps network admins to find out about
open relays in their networks. Exim and ORBS are great if you use ORBS
for generating warnings, not rejecting mail. Let me explain why:
ORBS by definition has no false positives, because it simply lists relays.
Relays are often abused for spam, but that's beside the point. Open
relays should be identified and closed to make life harder for spammers.
If you reject mail from hosts that are in the ORBS zone, your policy is:
"I don't want to get mail from sites run by technically incompetent admins
or networks with a questionable policy that forbids to identify sites
run by technically incompetent admins". That's not the same as: "I don't
want spam."
For further questions, simply visit
www.orbs.org yourself. If you run a
network, then I highly recommend to get ORBS database dumps for your
IP blocks.
Indeed, many mails are sent via open relays. Try to hire a good postmaster
and you will soon know why.
Michael
PS: I would rather not discuss the question if ORBS should be illegal or
if above.net is a spammer-friendly provider on this list. Feel free
to do so by private mail to me.
PPS:If there is a good and up-to-date comparison of RBL zones with their
policies, the Exim manual should point to it.
