F=F

Need From: in header

All versions

The F=F delivery agent flag is used by sendmail.cf header commands to force the inclusion of sender ("From") information (F=):

H?F?Re-sent-From: $q
H?F?From: $q

The F=F delivery agent flag has no special internal meaning to sendmail. It is a convention that is used only in the assorted "From:" header definitions (From:). See F= for a general description of this process.