@example
/usr/local/etc/postfix/master.cf:
nncp unix - n n - - pipe
- flags=F user=nncp argv=nncp-exec -quiet $nexthop sendmail $recipient
+ flags=Rqhu user=nncp argv=nncp-exec -quiet $nexthop sendmail $recipient
@end example
This runs the @command{nncp-exec} command to place outgoing mail into
-the NNCP queue after replacing @var{$nexthop} by the the receiving NNCP
+the NNCP queue after replacing @var{$nexthop} by the receiving NNCP
node and after replacing @var{$recipient} by the recipients. The
@command{pipe(8)} delivery agent executes the @command{nncp-exec}
command without assistance from the shell, so there are no problems with
shell meta characters in command-line parameters.
+Pay attention to @code{flags}, containing @code{R}, telling Postfix to
+include @code{Return-Path:} header. Otherwise that envelope sender
+information may be lost. Possibly you will also need somehow to
+preserve that header on the receiving side, because @command{sendmail}
+command will replace it. For example you can rename it before feeding to
+@command{sendmail} with
+@code{reformail -R Return-Path: X-Original-Return-Path: | sendmail}, or
+extract with:
+
+@verbatiminclude sendmail.sh
+
+Also pay attention that @command{maildrop} does not like @code{From_}
+mbox-style header, so you possibly want:
+
+@example
+mailbox_command = reformail -f0 | maildrop -d $@{USER@}
+@end example
+
@item Specify that mail for @emph{example.com}, should be delivered via
NNCP, to a host named @emph{nncp-host}:
@example
/usr/local/etc/postfix/master.cf:
nncp unix - n n - - pipe
- flags=F user=nncp argv=nncp-exec -quiet $nexthop sendmail $recipient
+ flags=Fqhu user=nncp argv=nncp-exec -quiet $nexthop sendmail $recipient
@end example
This runs the @command{nncp-exec} command to place outgoing mail into