-meaningful to various nmh programs.
-
-.in +.5i
-.ti -.5i
-Date:
-.br
-Added by \fIpost\fR\0(8), contains date and time of the message's entry
-into the mail transport system.
-
-.ti -.5i
-From:
-.br
-Added by \fIpost\fR\0(8), contains the address of the author or authors
-(may be more than one if a \*(lqSender:\*(rq field is present). For a
-standard reply (using \fIrepl\fR), the reply address is constructed by
-checking the following headers (in this order): \*(lqMail-Reply\-To:\*(rq,
-\*(lqReply\-To:\*(rq, \*(lqFrom:\*(rq, \*(lqSender:\*(rq.
-
-.ti -.5i
-Mail\-Reply\-To:
-.br
-For a standard reply (using \fIrepl\fR), the reply address is
-constructed by checking the following headers (in this order):
-\*(lqMail-Reply\-To:\*(rq, \*(lqReply\-To:\*(rq, \*(lqFrom:\*(rq,
-\*(lqSender:\*(rq.
-
-.ti -.5i
-Mail\-Followup\-To:
-.br
-When making a \*(lqgroup\*(rq reply (using \fIrepl\fR -group), any
-addresses in this field will take precedence, and no other reply address
+meaningful to various
+.B nmh
+programs.
+.PP
+.BR Date :
+.RS 5
+Added by
+.BR post ,
+contains date and time of the message's entry into the mail transport system.
+.RE
+.PP
+.BR From :
+.RS 5
+This header is filled in by default with the system's idea of the user's local
+mailbox. This can be changed with the
+.B Local\-Mailbox
+profile entry.
+It contains the address of the author or authors (may be more than one if a
+\*(lqSender:\*(rq field is present). For a standard reply (using
+.BR repl ),
+the reply address is constructed by checking the following headers (in this
+order): \*(lqMail-Reply\-To:\*(rq, \*(lqReply\-To:\*(rq, \*(lqFrom:\*(rq,
+\*(lqSender:\*(rq. A \*(lqFrom:\*(rq header MUST exist when the message is
+sent to
+.BR post ,
+otherwise the message will be rejected.
+.RE
+.PP
+.BR Envelope\-From :
+.RS 5
+Used by
+.B post
+to specify a value for the sender's envelope address to the mail transport
+system. If omitted,
+.B post
+will use the value of the \*(lqSender:\*(rq or the \*(lqFrom:\*(rq header.
+See
+.IR send (1)
+for more details.
+.RE
+.PP
+.BR Mail\-Reply\-To :
+.RS 5
+For a standard reply (using
+.BR repl ),
+the reply address is constructed by checking the following headers
+(in this order): \*(lqMail-Reply\-To:\*(rq, \*(lqReply\-To:\*(rq,
+\*(lqFrom:\*(rq, \*(lqSender:\*(rq.
+.RE
+.PP
+.BR Mail\-Followup\-To :
+.RS 5
+When making a \*(lqgroup\*(rq reply (using
+.B repl
+.BR \-group ),
+any addresses in this field will take precedence, and no other reply address