On Tue, 2011-01-18 at 09:00 -0500, Bowie Bailey wrote: > On 1/18/2011 4:13 AM, J4 wrote: > > > > I have Dovecot LDA so Sieve might well be a good idea, but I would > > like to inform the sender that the Email was dropped as spam, and > > avoid backscatter. I don't think I can do this with Sieve/Dovecot LDA. > > You cannot do this from the delivery agent without creating > backscatter. If you want to inform the sender, the only reliable way to > do it is to scan the message when it first comes in and simply reject > the spam. This way, you never accept the message and the sending system > is responsible for notifying the sender that the message did not go through. > If you're thinking of detecting spam at SMTP time you should consider greylisting. When my ISP implemented it the spam I get dropped immediately from 80% of my mail to 8%, where its remained ever since. After that you can take a view whether you want to:
- scan the remaining mail at SMTP time (and reject spam as you originally described) - use SA as an MTA filter and let the recipient's MUA put it in a spam folder or bin depending on what the user decides. Or your MTA filter could silently bin spam or feed it to Bayes to be learned as spam. Your choice: you just can't reject it at this stage. - use a procmail recipe to scan mail and either reject spam or pass it to the recipient's MUA as above. Use this if you want the recipients to have some control over spam recognition, individual Bayes filters, etc. Martin
