On Tue, Jan 12, 2010 at 10:39:16AM -0800, Aaron Clausen wrote:
> Are challenge response systems still heavily frowned on?
Yes. This is how I explain spam filtering of C/R requests to
my users:
The attached message was reported by you as a quarantine error.
Sadly, challenge/response anti-spam systems are in turn significant
contributors to the spam volume on the Internet, because spammers
and viruses forge the sender addresses of email, and users who never
sent mail get challenged to prove their intent to send mail they
never sent.
When you find challenges in the quarantine in response to email
you actually sent, by all means release them and respond. If it
is not inappropriate to do so, perhaps you could suggest to the
recipient that such systems are not a socially responsible way to
stop unwanted email.
Either the sender is unforged and not a spammer, and the challenge
is an unnecessary hurdle, or the sender was forged and the challenge
is unwarranted junk mail. Thus challenge-response anti-spam systems
are always wrong.
Thank you for taking the time to report quarantine errors, while this
type of message will continue to be blocked in the future, we are
in most other cases successful in getting erroneous identification
of legitimate mail to stop.
--
Viktor.
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