WhiteList JetPack IP addresses
# Block WordPress xmlrpc.php requests
<Files xmlrpc.php>
order deny,allow
deny from all
allow from 220.239.238.83
allow from 192.0.64.0/18
allow from 209.15.0.0/16
allow from 66.155.0.0/17
allow from 185.64.140.0/22
</Files>