I love spamgourmet, it works wonders, and within it's concepts lie the key to truly making spam unprofitable. So, on our quest to make spam unprofitable, let's ensure that we don't go broke in the meantime!
Right now, if a spam message is going to be 'eaten' we have to accept the message. Then it is analyzed and dropped. Well, what if we could perform this analysis BEFORE the message is even sent.
Using a sendmail milter, we can analyze the address provided to the RCPT TO: SMTP command, and see if this address is allowed any more e-mail. If it is, the spamgourmet milter will accept it as it always has. If the address is no longer valid or has expired, we return an SMTP error code stating that 'the user account no longer exists." This will tell the sender the account is dead. By doing this, we most likely have removed the address from a particular spammers list, so we won't get asked again, but also, the message was never sent to us, we blocked it, before the SMTP DATA command could be issued. Thus saving loads of bandwidth and processor time. (We didn't have to parse any message!)
I'd like to write this milter up in C. A PERL version is just as likely, but a C one is native and would be much more efficient. It'd give us alot of flexibility, and save alot of bandwidth from being needlessly wasted.
What are your opinions!? :)
Mike.