Echo only IP's? Script not working..

[akiznin]

My script I made is not working correctly, its supposed to only echo the IP's it finds on a website but still shows entire site.

 

<?php
$fn = "website.com";
$file = file_get_contents($fn);
$file = preg_replace('/^(([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]).){3}([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$/','',$file);
echo $file;
?>