<?php
ini_set("diplay_errors", 0); // make sure there is no unexpected output while in production mode
$theIP = $_SERVER['REMOTE_ADDR'];
$ips = "ips.txt"; // a file writable by the web server
$list = file($ips);

foreach ($list as $key => $ip) {
        $list[$key] = trim($ip);
}

if ( !in_array($theIP, $list) ) {
	array_push($list, $theIP);
mail("you@somesite.com", "New IP Address", "{$theIP} -> " . gethostbyaddr($theIP), "From: me@mycomputer.com");
	exec("echo '{$theIP}' >> {$ips}");
}
?>