> I am new to postfix and spamassassin, but we are already > using greylist, and I liked a lot what you said here. > > How can I greylist messages by means of RBL checking? How > should I setup Postfix to do that? > > Regards, > Carlos.
I am not a Postfix expert, and cannot really call myself an Exim expert either but the strategy goes something like this: During (various) SMTP ACL (Access Control Lists) run the checks for things like RBL etc (this is easy in Exim) and mark the results (in either an ACL variable or by adding a header.*) * Header had the disadvantage of requiring the Greylist check to wait until "SMTP DATA" time where the headers are available when all we really need is SenderIP-FromName-RCPT which are all available by RCPT ACL time. When you have made all of your checks, and before checking SpamAssassin, run the Greylist on any message that was "flagged" above -- if the greylist returns true this is where we tempfail (Defer in Exim) the message. Presuming that nothing flags the message as needing greylisting or it passes greylisting, run SA. -- if SPAM (or perhaps some special threshold higher or lower than 'normal' spam threshold) AND there is NO greylist flag (it hasn't been greylisted yet) then RUN the greylist check now, after the SA check. The idea is that there is no point in SA checking something that will be greylisted anyway -- and there is no point in greylisting something "twice". -- Herb Martin
