(2) Services -> HTTP Blacklist and get the key (12 alphabets) for yourself.
(3) copy XOOPS_TRUST_PATH/modules/protector/filters_disabled/postcommon_post_deny_by_httpbl.php into XOOPS_TRUST_PATH/modules/protector/filters_enabled/
(4) modify '............' into your key in the file.
// get your 12-character access key from http://www.projecthoneypot.org/
define( 'PROTECTOR_HTTPBL_KEY' , '............' ) ;