On Thu, 1 May 2003, joe wrote:Well, I may have oversimplified things -
Postfix can filter mail on any header regexp - your choice of posix or perl regexps in fact.
No milter needed, postfix does this in a stage called "header checks"
What are the header checks done?
The best bet is to analyze this information:
http://www.postfix.org/big-picture.html
Everything, before the 'data' call or only from and to type headers etc etc? At what stage does it check and reject the subject or content type ?
Obviously it's impossible to scan content without reading content, so there are several stages in which postfix can reject messages.
Just like sendmail, it can use RBLs & access lists to terminate sessions based on the data available during the smtp handshake - then it can later apply regex patterns to any headers as well as the body, and send the message through any of a choice of filters, or no filter at all, based on the results. It can also hand off messages to procmail or spamassassin, as is our custom.
Joe
