simple mass RBL check

massrbl.php

<?php
function rblcheck($host) { // Note: I have no idea how well suited CBL is for this purpose. If it gets annoying we can remove it ~ Aurora
        $rbls = array('sbl-xbl.spamhaus.org', 'rbl.efnet.org', 'cbl.abuseat.org', 'dnsbl.dronebl.org');
        foreach($rbls as $rbl) {
                $lookup = implode('.', array_reverse(explode('.', $host))) . '.' . $rbl;
                if (strstr(gethostbyname($lookup), "127.0.0")) {
                        return $rbl;
                } 
        }
        return 0;
}
if(isset($_FILES['proxyfile']['tmp_name'])) {
    $proxies = file_get_contents($_FILES['proxyfile']['tmp_name']);
    $proxylist = explode("\n", $proxies);
    foreach($proxylist as $proxy) {
        $proxy = str_replace("\r","",$proxy);
        $withoutport = explode(":",$proxy);
        $withoutport = $withoutport[0];
        if($check = rblcheck($withoutport)) {
          print("");
        }
       else { print("$proxy<br>"); }
}
}
?>

<form action="rbl.php" method="post" enctype="multipart/form-data">
<input type="file"  name="proxyfile" />
<input type="submit" value="Upload proxy list" />
</form>