Email Program / Service that will hold messages until sender fills out a CAPTCHA

Tag: email , spam-prevention , spam-blocking Author: mochaq Date: 2010-08-29

I'm looking for the following service >>

When a person emails an individual, the email goes into a temp hold inbox that they do not see. The person who sent the email will receive an auto responder asking them if they are a real person and they have to fill out a CAPTCHA or something along those lines for the message to be released onto the client.

Thank you in advance! Brandon

Other Answer1

What you are looking for is called "Challenge-Response spam protection"; you may want to read the Wikipedia article on C/R spam protection. There is some software out there that does this, but this technique is not often seen.

And this is for a reason. Consider that

  • Delivery Notifications will have an empty <> Return-Path and will not pass the filter
  • C/R places a burden too heavy on the sender. I have sent around 15 different mails today, 4 of them to previously unknown contacts. I would not bother doing 4 captchas.
  • Many Captchas are inaccessible for e.g. blind users

Consider using some other anti-spam technique. Why would you need to do something that nobody else does?

Other Answer2

Why not just force the user to fill out a captcha before the email is sent? It reduces the need for holding temporary emails.