<?php
$sorgu = 'select count(substring_index(ip,".",1)) as toplam,
substring_index(ip,".",1) as ip 
from ipler group by ip';

$sorgula = mysql_query($sorgu);
while($sonuc = mysql_fetch_assoc($sorgula)) echo $sonuc['ip'].' ile başlayan '.$sonuc['toplam'].' adres var <br />';

?>