if (exists $mail{ruleset} and exists $mail{arg1}) {
    $mail{ruleset} eq 'check_mail'  and $mail{from}  = $mail{arg1};
    $mail{ruleset} eq 'check_rcpt'  and $mail{to}    = $mail{arg1};
    $mail{ruleset} eq 'check_relay' and $mail{relay} = $mail{arg1};


##</code><code>##

Nov 27 15:08:23 sender03 sendmail[1016]: lARN8MsF001016: Milter
insert (1): header: DKIM-Signature:  v=1; a=rsa-sha256;
c=simple/simple;\n\td=yahoo.com; s=1319567451;