Spam and dangerous spam

/***************************
   START SPAM PROTECTION
***************************/

// Address of the blocklist server
$checkspam['blocklist'] = 'sbl.spamhaus.org';

// Build the url to check (reverse DNS query). If you want to test if it works on
// your server, replace the "get_remote_address()" part with the following: '127.0.0.2'
$checkspam['Reverse DNS'] = implode( '.', array_reverse( explode( '.', get_remote_address() ) ) ) . '.' . $checkspam['blocklist'];

// Do the actual lookup. If the users IP is listed in the blocklist, we will be given just an IP back from the queried server.
// If the user is *not* listed as a spammer, the result we get back from the server will be the same string as we sent.
if( $checkspam['Reverse DNS'] != gethostbyname($checkspam['Reverse DNS']) ) {
    
    message('Unfortunately, it would appear that your current IP address is listed in one of the anti-spam databases we queried.
            Because of this, you will not be able to register a new account at this point in time. If you believe this to
            be a mistake, we urge you to read the FAQ over at <a href="http://www.spamhaus.org/faq/index.lasso">The Spamhaus Project</a>
            for more details, including actions you can take to resolve this issue.',true);
}

/****************************
   END OF SPAM PROTECTION
****************************/