Kens Spam Filter 3

Kens Spam Filter sits in between your normal mail program and the outside world, everything you send passes out through the filter, and everything you receive also passes through it.

It has two lists, a list of email addresses from whom it will accept mail, and a list of email addresses that it will reject mail from.

When a message arrives from an unknown user the message is held and a reply generated and sent back to the sender asking them to reply back with a subject line that contains a keyword, this keyword is the letters KSF followed by a short serial number.

If they reply back, all future messages from that person will pass through the filter, and all presently held messages from that email address will be released.

If they don't reply any future messages from them will be ignored, most spammers don't even use real addresses, so they won't ever see the registration request.