我使用哪种方法来获取每台计算机的ip地址

我们办公室有50多台电脑，每台电脑都有来自当地服务提供商的独立互联网连接。现在在我们的网站上，我们想在用户注册时获得每台计算机的信息（我不知道没有ip有任何其他方式）。

因此，作为一种正常的方法，我们使用了$ip = $_SERVER['SERVER_ADDR'];，但它对所有计算机/连接显示相同的ip。

在这里stackoverflow，我找到了许多解决方案来获得真正的ip。但我很困惑，在我们网站的注册过程中，什么能更好地获得each computer ip。

方法1:

getenv() is used to get the value of an environment variable in PHP.
// Function to get the client IP address
function get_client_ip() {
$ipaddress = '';
if (getenv('HTTP_CLIENT_IP'))
    $ipaddress = getenv('HTTP_CLIENT_IP');
else if(getenv('HTTP_X_FORWARDED_FOR'))
    $ipaddress = getenv('HTTP_X_FORWARDED_FOR');
else if(getenv('HTTP_X_FORWARDED'))
    $ipaddress = getenv('HTTP_X_FORWARDED');
else if(getenv('HTTP_FORWARDED_FOR'))
    $ipaddress = getenv('HTTP_FORWARDED_FOR');
else if(getenv('HTTP_FORWARDED'))
   $ipaddress = getenv('HTTP_FORWARDED');
else if(getenv('REMOTE_ADDR'))
    $ipaddress = getenv('REMOTE_ADDR');
else
    $ipaddress = 'UNKNOWN';
return $ipaddress;
}
$_SERVER is an array that contains server variables created by the web server.
// Function to get the client IP address
function get_client_ip() {
$ipaddress = '';
if ($_SERVER['HTTP_CLIENT_IP'])
    $ipaddress = $_SERVER['HTTP_CLIENT_IP'];
else if($_SERVER['HTTP_X_FORWARDED_FOR'])
    $ipaddress = $_SERVER['HTTP_X_FORWARDED_FOR'];
else if($_SERVER['HTTP_X_FORWARDED'])
    $ipaddress = $_SERVER['HTTP_X_FORWARDED'];
else if($_SERVER['HTTP_FORWARDED_FOR'])
    $ipaddress = $_SERVER['HTTP_FORWARDED_FOR'];
else if($_SERVER['HTTP_FORWARDED'])
    $ipaddress = $_SERVER['HTTP_FORWARDED'];
else if($_SERVER['REMOTE_ADDR'])
    $ipaddress = $_SERVER['REMOTE_ADDR'];
else
    $ipaddress = 'UNKNOWN';
return $ipaddress;
}

方法2:

$host= gethostname();
$ip = gethostbyname($host);

方法3：

$ip = getenv('HTTP_CLIENT_IP')?:
getenv('HTTP_X_FORWARDED_FOR')?:
getenv('HTTP_X_FORWARDED')?:
getenv('HTTP_FORWARDED_FOR')?:
getenv('HTTP_FORWARDED')?:
getenv('REMOTE_ADDR');

方法4：（最先进的方法）

function get_ip_address() {
// check for shared internet/ISP IP
if (!empty($_SERVER['HTTP_CLIENT_IP']) && validate_ip($_SERVER['HTTP_CLIENT_IP'])) {
    return $_SERVER['HTTP_CLIENT_IP'];
}
// check for IPs passing through proxies
if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
    // check if multiple ips exist in var
    if (strpos($_SERVER['HTTP_X_FORWARDED_FOR'], ',') !== false) {
        $iplist = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
        foreach ($iplist as $ip) {
            if (validate_ip($ip))
                return $ip;
        }
    } else {
        if (validate_ip($_SERVER['HTTP_X_FORWARDED_FOR']))
            return $_SERVER['HTTP_X_FORWARDED_FOR'];
    }
}
if (!empty($_SERVER['HTTP_X_FORWARDED']) && validate_ip($_SERVER['HTTP_X_FORWARDED']))
    return $_SERVER['HTTP_X_FORWARDED'];
if (!empty($_SERVER['HTTP_X_CLUSTER_CLIENT_IP']) && validate_ip($_SERVER['HTTP_X_CLUSTER_CLIENT_IP']))
    return $_SERVER['HTTP_X_CLUSTER_CLIENT_IP'];
if (!empty($_SERVER['HTTP_FORWARDED_FOR']) && validate_ip($_SERVER['HTTP_FORWARDED_FOR']))
    return $_SERVER['HTTP_FORWARDED_FOR'];
if (!empty($_SERVER['HTTP_FORWARDED']) && validate_ip($_SERVER['HTTP_FORWARDED']))
    return $_SERVER['HTTP_FORWARDED'];
// return unreliable ip since all else failed
return $_SERVER['REMOTE_ADDR'];
}
/**
 * Ensures an ip address is both a valid IP and does not fall within
 * a private network range.
 */
function validate_ip($ip) {
if (strtolower($ip) === 'unknown')
    return false;
// generate ipv4 network address
$ip = ip2long($ip);
// if the ip is set and not equivalent to 255.255.255.255
if ($ip !== false && $ip !== -1) {
    // make sure to get unsigned long representation of ip
    // due to discrepancies between 32 and 64 bit OSes and
    // signed numbers (ints default to signed in PHP)
    $ip = sprintf('%u', $ip);
    // do private network range checking
    if ($ip >= 0 && $ip <= 50331647) return false;
    if ($ip >= 167772160 && $ip <= 184549375) return false;
    if ($ip >= 2130706432 && $ip <= 2147483647) return false;
    if ($ip >= 2851995648 && $ip <= 2852061183) return false;
    if ($ip >= 2886729728 && $ip <= 2887778303) return false;
    if ($ip >;= 3221225984 && $ip <= 3221226239) return false;
    if ($ip >;= 3232235520 && $ip <= 3232301055) return false;
    if ($ip >= 4294967040) return false;
}
return true;
}