Something that was mentioned a few months ago in some other email-related
mailing lists I subscribe to, has been raised again. I'd like to find out
if the following 'feature' is both desirable and relatively simple to
implement:
Right now the exim configuration allows either *_{accept|reject} or
*_{accept|reject}accept_recipients to be set, which allows the local admin
to refuse unwanted (usually spammer) calls on either a per-connection or
per-recipient basis. Obviously the latter is more successful at wasting
the resources of the source of such mail.
There appears to be a significant number of admins who wish to not only
reject spam, but also actively participate in making life difficult for
spammers, and making spammers' endeavour more difficult by wasting more
resources, reducing their efficiency and increasing their costs. The
intent, of course, is to make spamming economically less attractive, since
greed may be the only (dis)incentive some spammer have.
Here's the suggestion: allow another config option that would put exim
into 'tar baby' mode if the sending host meets local criteria as a
spammer. If set, calls from said hosts would be rejected on a
per-recipient basis, but that all exim responses deliberately happen
v-e-r-y s-l-o-w-l-y. Maybe one character per second for the rejection
notices. You're not only refusing their intended action, but in doing so
you're wasting time of theirs and significantly reducing their efficiency
at spamming. By the time they even realize you're doing this deliberately,
you've done some real damage to their bottom line.
Philip, would it be difficult to implent config options of, say:
relay_reject_slow
host_reject_slow
Would this be reasonable? Practical? Is there even consensus that this
might be a Good Thing? My instinct suggests that a combination of the RBL
facility and slow-rejection may be the best anti-spam measure available,
short of state (attempts to impose) regulation.
------------------------------------------------------------------------------
Evan Leibovitch, Sound Software Ltd, located in beautiful Brampton, Ontario
Supporting PC-based Unix since 1985 / Caldera & SCO authorized /
www.telly.org
----------------- HURD is to Linux as Plan 9 is to System V ------------------
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