[Mimedefang] OT: Sendmail "Active-Directory"-type question

[Kevin A. McGrail]

This is not really for just one server but more for the many servers we do
backup MX for that the spammers have more and more been thinking they could
bypass the SPAM filter by sending to out of order MX records.

However, this is an interesting interim fix.  Quick question, in the
mimedefang-filter man page, you have a demo for the
md_check_against_smtp_server that has a filter_recipient that doesn't end
with return ('CONTINUE', "ok");  Should that really be added i.e. something
like this?

sub filter_recipient {
  my($recip, $sender, $ip, $host, $first, $helo, $rcpt_mailer, $rcpt_host,
$rcpt_addr) = @_;

  if ($recip =~ /server.checkagainst.domain/i) {
    return md_check_against_smtp_server($sender, $recip, "helo.domain",
"server.checkagainst.domain");
  }

  return ('CONTINUE', "ok");
}

Regards,
KAM

> Why do you need that?  You can use md_check_against_smtp_server because
> Sendmail is sensible and (normally) validates recipients at RCPT TO: time.
>
> In general, because of Sendmail's flexibility, there is no way to
enumerate
> all local users -- you have to know details of your particular site's
> setup and kludge it.