Re: [exim] Are you human?

David Cantrell wrote:
> On Tue, Aug 11, 2009 at 06:30:39PM -0500, Exim wrote:
>
>> I just had a client ask for something I haven't done. He wants emails from
>> unknown users to be sent back with a "are you human" request they must
>> respond to correctly. If they do, then they will be automatically added to
>> a list of valid senders.
>>
>> (and no I don't want to do this, but sometimes you have to do what the
>> client demands, rather than what is really best for them).
>
> Yes, you do. But that doesn't stop you from trying to dissuade them!
> My argument against it is thus:
>
> Spammers rarely send email with legitimate From: headers - when the
> address exists at all, it's almost always that of some poor innocent.
> So, when you send the "are you real?" email, you're either annoying
> some legitimate email sender (and potentially losing their business) or
> you're sending it to someone who has never heard of you. In that latter
> case they're likely to say "yes!" just to piss you off and let the spam
> through. But more importantly, challenge/response IS SPAM, because it
> is unsolicited bulk email. No-one solicits it - your legitimate
> correspondents never asked for it, and obviously the poor innocents
> you're subjecting to it didn't either. And it's bulk, because it is
> sent with substantively the same content to every recipient without
> regard for whether the recipient is me or the king of the moon.
>

Not mentionning that your server will ultimately get blacklisted at some
point, even automatically if you send such an automated reply to a spamtrap.