In other words, what Sieve implementations can be configured such that a
reject causes the email to be refused/not accepted during the SMTP
transaction, instead of accepted, and then bounced back to the alleged
sender (often, in the case of spam, a Joe-Job victim). Someone just
told me that Cyrus' implementation can't do this.
Somewhat of a late post I know, but Rockliffe's Mailsite has a Server Sieve
Script where if you use "Reject" it will reject at the SMTP protocol level.
I doubt this is much use to you as presumably you are looking for something
that is available at the end user level (as I can see in your I-Draft).
The problem with filtering before storing in the end users mailbox is as Ned
says, the concept of the mail envelope. At the SMTP level, the envelope
probably has many recipients, so who's configuration do you use? It's only
when you are about to put a message in a users INBOX will you know that you
can take action on behalf of all the recipients (cos there is only one).
Hence when MailSite rejects a message at the SMTP level it is using a global
server level script.
A comment on your I-Draft. I've never heard of "joe-job spam". Now I know
I only code mail servers, not use them, so perhaps I'm just ignorant, but
I'm wondering if "joe-job spam" is a well established enough term to be
using without describing what it means? I see you do describe it
eventually, but wonder if you can avoid the term completly in the I-Draft.
Nigel