Checking URL against down blacklist servers

<?php
require_once( dirname(__FILE__).'/includes/load-yourls.php' );

// Let's test a legit URL
$url = 'https://www.google.com/';

// Below is code from the plugin, modified to var_dump() instead of return a result

$parsed = parse_url( $url );

if( !isset( $parsed['host'] ) )
    return yourls_apply_filter( 'ozh_yourls_antispam_malformed', 'malformed' );

// Remove www. from domain (but not from www.com)
$parsed['host'] = preg_replace( '/^www\.(.+\.)/i', '$1', $parsed['host'] );

// Major blacklists. There's a filter if you want to manipulate this.
$blacklists = yourls_apply_filter( 'ozh_yourls_antispam_list',
    array(
        'zen.spamhaus.org',
        'multi.surbl.org',
        'black.uribl.com',
        'nope.niet.nein',
    )
);

// Check against each blacklist, exit if blacklisted
foreach( $blacklists as $blacklist ) {
    $domain = $parsed['host'] . '.' . $blacklist . '.';
    $record = @dns_get_record( $domain );

    var_dump( $blacklist, $record );
}

/* RESULT :
 **********

string 'zen.spamhaus.org' (length=16)

array (size=0)
  empty

string 'multi.surbl.org' (length=15)

array (size=0)
  empty

string 'black.uribl.com' (length=15)

array (size=0)
  empty

string 'nope.niet.nein' (length=14)

array (size=0)
  empty

*/