This code allows to get the IP address from which the user is viewing the current page.

Get Remote IP Address in PHP

<?php          
/* Source: http://www.apphp.com/index.php?snippet=php-get-remote-ip-address */

function getRemoteIPAddress(){
    $ip = isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR'] : '';
    return $ip;
}
 
/* If your visitor comes from proxy server you have use another function
to get a real IP address: */
function getRealIPAddress(){   
    if(!empty($_SERVER['HTTP_CLIENT_IP'])){
        //check ip from share internet
        $ip = $_SERVER['HTTP_CLIENT_IP'];
    }else if(!empty($_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;
}
?>