Spam Email Verification: Is there software to require email senders to type a security code before email sent?

I want software (or plugin for Outlook/Entourage) to allow me to control spam emails. I'd like to be able to add senders to an approved list. If the sender is not on the approved list, they receive an automatic "reply email" requesting that they type in a verification code shown in a graphic. This allows the original message to be received but blocks automatic senders who don't reply with the verification code. Sender may still be added to a blocked list at the user's discretion.

Spam Email Verification: Is there software to require email senders to type a security code before email sent?
The type of approach that you describe has already been widely tried and discarded. There were some major email providers that had this functionality not too long ago, but it simply doesn't work effectively - many legitimate users won't bother with the message that you automatically send to them. You not think that would be the case, but it's already been shown to be true.
Reply:Here are two sites to check out some free Anti-spam programs. The second one lists several programs.





http://www.spambutcher.com/spamblockings...





http://netsecurity.about.com/od/emailspa...
Reply:NO

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