You're welcome to use whatever you like on your systems, but FYI here's a
post I made on the iserver list regarding challenge-response systems:
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1)As a business, if someone signs up for my newsletter, I'm going to be
assaulted with many of these 'challenge' emails to send out every time I send
a new issue. Some systems require that you re-send the email from a specific
address with a key-code in the subject line. For a large automated list using
mailman or majordomo, this can be cost-prohibitive and will probably result
in me not completing any of them.
2)What if my online store sends an email receipt which gets blocked by a
challenge response system? I don't want to take the time to reply to all the
challenges, and then a customer complains that he never got his receipt, or
figures that it didn't go thru and places the order again, etc., etc.,
3)What if a virus sends this person an email, and it bounces with the
challenge to the original virus victim? (or a third party?) What if THAT
person has a challenge system and sends a challenge BACK to the first
recipient. Will this create a mail loop? If not, how does the challenge
system detect that it is another challenge and not send a reply? how long
will it take for spammers to figure out that system to get their emails to
bypass the challenge system?
4)As a consumer, if I'm trying to contact a business, I don't want the 3rd
degree when trying to buy Something. Think about the dial-up user: They
send an email, get off line until the next day, when they find that they have
to send a challenege response back just to make their FIRST email (from
yesterday) get delivered, which is just frustrating and will negatively
impact their feeling of this business.
5)As an ISP/mail host, some spammer uses your domain as a reply-to address.
So you get all these challenges to emails you never sent that you now have to
sort thru one-by-one, since you're not sure which of them are real and which
are as a result of a spammer abusing your domain name.
True, no system is perfect, but I'd much rather take my chances with
spamassassin letting spam thru then deal with a '100% spam solution' (their
words) that has these major problems with them.
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Also, here's an old but still valid opinion from CNET:
http://news.com.com/2010-1071_3-1009745.html
Have fun!
Matt
At 8:38 AM -0700 1/17/05, Jonathan Duncan said something about:
This was discussed a while back. Which, if any, Challenge Response Systems
(CRS) are people using and liking? spam.abuse.net refers to Spam