prova così:

<?php
$getip = $_SERVER["REMOTE_ADDR"];
$banned_ip = array();
$banned_ip[] = '62.';
$banned_ip[] = '171.';
$banned_ip[] = '172.';

foreach($banned_ip as $banned)
{
if ($ip==$blacked || strpos($ip,$banned) === 0 )
{
echo "ERRORE

";
exit;
}
}

?>