[Mimedefang] Spamassassin 3.0 + MD 2.42

[Nelson1 at cog7.org]

Here is SPF check I am using in mimedefang-filter.  Was thinking of moving
to filter_begin so action_add_header would work.  Logging SPF info to
/etc/mail/spflist (amazing how many non-spammers send us e-mail as
ourselves).  Also sendmail had trouble returning the "%40" in $smtp_comment
so removed that...

#Must enable SENDER_CHECK in /etc/init.d/sendmail
sub filter_sender {
  my($sender, $ip, $hostname, $helo) = @_;
    use Mail::SPF::Query;
    my $query = new Mail::SPF::Query (ip => $ip, sender=>$sender,
helo=>$helo, trusted=>1, guess=>0);
    my ($result,           # pass | fail | softfail | neutral | none | error
| unknown [mechanism]
        $smtp_comment,     # "please see http://spf.pobox.com/why.html?..."
when rejecting, return this string to the SMTP client
        $header_comment,   # prepend_header("Received-SPF" => "$result
($header_comment)")
        $spf_record,       # "v=spf1 ..." original SPF record for the domain
       ) = $query->result();
    #action_add_header('Received-SPF', "$result ($header_comment)");
    if ($result ne "none") {
      open(SPF, ">>/etc/mail/spflist");
      print SPF "$result $ip $sender $helo $spf_record\n";
      close(SPF);
      }
    $from = $sender;
    $from =~ s/[<>]//g;
    #$from =~ s/@/%40/g;
    if    ($result eq "pass") { return (CONTINUE,"ok"); }
    elsif ($result eq "fail") { return (REJECT,"Sorry $sender not permitted,
please see http://spf.pobox.com/why.html?sender=$from&ip=$ip "); }
  return (CONTINUE,"ok");
}