Andreas Schulze: > Hello, > > I have to add a "Reply-To" Header in (smtp-) submitted messages. > > Adding it unconditionally using PREPEND result in messages with more > then one instance > of this header which violates RFC5322. > Is there a way to add a header _only_ if not present?
header_checks has no memory, so you need to use a Milter
(Python, Perl, C) or SMTP-based filter.
Wietse
