Определение IP-адреса посетителя

gistfile1.php

<?php
function getRealIPAddr() 
{
    if (!empty($_SERVER['HTTP_CLIENT_IP'])) { //check ip from share internet
        $ip=$_SERVER['HTTP_CLIENT_IP'];
    } elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) { //to check ip is pass from proxy
        $ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
    } else {
        $ip=$_SERVER['REMOTE_ADDR'];
    }
    return $ip;
}