Does postfix offer anti-spam support at the connect level?Absolutely -
For example, MimeDefang can drop an incomming spam email during the connection thanks to sendmail milter support?
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"
Does postfix have a milter equivelant?
Postfix has a totally different architecture, so sendmail-specific architectural add-ons don't make sense here.
Don't get me wrong, sendmail is a good MTA - most would-be replacements fall far short in terms of features and flexibility - but we've concluded that postfix (& only postfix so far) is worthy to assume sendmail's duties here.
Joe
