Interesting question - I think they would have to pre-whitelist the mailing list address in order to subscibe successfully - it wasn't my system though - a commercial offering I saw which I thought had some unique advantages - this TDMA that Julian mentions might work similarly...
I just tried it out - the TDMA (www.tdma.net) replies with a message (pasted below for reference). This is exactly the sort of thing I was thinking of - haven't looked at how easy it is to integrate with courier, but I imagine it wouldn't be hard - received but "undelivered" messages could actually be stored in a special folder - like a spam folder - with the same auto-purge option as "Trash". - so that would allow you to still receive (when you are expecting it) and mail from lists or robots. Mail sent from a spammer will probably not have a valid return address, so they'll never see the reply. NEAT!. m/ This message was created automatically by mail delivery software (TMDA). Your message attached below is being held because the address <[EMAIL PROTECTED]> has not been verified. To release your message for delivery, please send an empty message to the following address, or use your mailer's "Reply" feature. [EMAIL PROTECTED] This confirmation verifies that your message is legitimate and not junk-mail. You should only have to confirm your address once. If you do not respond to this confirmation request within 14 days, your message will not be delivered. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Bill Michell Sent: Wednesday, January 07, 2004 3:55 PM To: 'Courier Users' Subject: RE: Alternative concepts to SPF vs. YASAF WAS RE: [courier-users] RE: freemail list and questions about yahoo... When you add yourself to a mailing list, how do you tell the system not to bounce the subscription confirmation message? What is your definition of a sender? -- Bill Michell [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mitch (WebCob) Sent: 07 January 2004 23:47 To: Gordon Messmer; Courier Users Subject: Alternative concepts to SPF vs. YASAF WAS RE: [courier-users] RE: freemail list and questions about yahoo... While we're all ranting (SPF vs. YASAF, etc.)... has anyone seen an open source equivalent of this system: All messages from unknown senders are bounced. The bounce contains a link to a robot-unfriendly "prove you are a human with a real email address page" that consists of one of those "enter the letters you see in this picture" forms. Doing that validates the sender as a real person, not a spammer, and eliminates the need to run something like spamassassin. A database is kept of all valid senders, and whitelists (discussion lists, etc.) to make this a one time requirement per recipient (or optionally per recipient domain, per server etc.) I'm thinking something like this could be added to courier as a filter - much like your filter concept Gord - just wanted to solicit opinions about it - the company I saw doing it was offering it as a mail filter service (set your MX to them, and tell them where to send the cleaned mail to IIRC) neat in a way... Thoughts? ------------------------------------------------------- This SF.net email is sponsored by: Perforce Software. Perforce is the Fast Software Configuration Management System offering advanced branching capabilities and atomic changes on 50+ platforms. Free Eval! http://www.perforce.com/perforce/loadprog.html _______________________________________________ courier-users mailing list [EMAIL PROTECTED] Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users ------------------------------------------------------- This SF.net email is sponsored by: Perforce Software. Perforce is the Fast Software Configuration Management System offering advanced branching capabilities and atomic changes on 50+ platforms. Free Eval! http://www.perforce.com/perforce/loadprog.html _______________________________________________ courier-users mailing list [EMAIL PROTECTED] Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users
