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. Disclaimer: off-list followups get on-list replies or get ignored. Please do not ignore the "Reply-To" header. To unsubscribe from the postfix-users list, visit http://www.postfix.org/lists.html or click the link below: <mailto:majord...@postfix.org?body=unsubscribe%20postfix-users> If my response solves your problem, the best way to thank me is to not send an "it worked, thanks" follow-up. If you must respond, please put "It worked, thanks" in the "Subject" so I can delete these quickly.