# Test if the email's sender is in the whitelist
 :0
 * ? formail -x"From" -x"From:" -x"Sender:" \
     -x"Reply-To:" -x"Return-Path:" -x"To:" \
         | egrep -is -f ~/.procmail/white.lst
{
 :0 fwh
      | formail -a"X-Match: whitelist"
}