试试这个:

 $_SERVER['REMOTE_ADDR'];

它应该包含在$_SERVER['REMOTE_ADDR']变量中。

这里有一个简单的一行代码

$ip = $_SERVER['HTTP_X_FORWARDED_FOR']?: $_SERVER['HTTP_CLIENT_IP']?: $_SERVER['REMOTE_ADDR'];

编辑:

上面的代码可能会返回保留地址(如10.0.0.1)，所有代理服务器的地址列表，等等。 要处理这些情况，请使用以下代码:

function valid_ip($ip) {
    // for list of reserved IP addresses, see https://en.wikipedia.org/wiki/Reserved_IP_addresses
    return $ip && substr($ip, 0, 4) != '127.' && substr($ip, 0, 4) != '127.' && substr($ip, 0, 3) != '10.' && substr($ip, 0, 2) != '0.' ? $ip : false;
}

function get_client_ip() {
    // using explode to get only client ip from list of forwarders. see https://en.wikipedia.org/wiki/X-Forwarded-For
    return
    @$_SERVER['HTTP_X_FORWARDED_FOR'] ? explode(',', $_SERVER['HTTP_X_FORWARDED_FOR'], 2)[0] :
    @$_SERVER['HTTP_CLIENT_IP'] ? explode(',', $_SERVER['HTTP_CLIENT_IP'], 2)[0] :
    valid_ip(@$_SERVER['REMOTE_ADDR']) ?:
    'UNKNOWN';
}

echo get_client_ip();

快速解决方案(无错误)

function getClientIP():string
{
    $keys=array('HTTP_CLIENT_IP','HTTP_X_FORWARDED_FOR','HTTP_X_FORWARDED','HTTP_FORWARDED_FOR','HTTP_FORWARDED','REMOTE_ADDR');
    foreach($keys as $k)
    {
        if (!empty($_SERVER[$k]) && filter_var($_SERVER[$k], FILTER_VALIDATE_IP))
        {
            return $_SERVER[$k];
        }
    }
    return "UNKNOWN";
}

我使用了其他答案之一，并添加了一些额外的东西，如CloudFlare代理和NGINX代理检测。

/**
 * Gets, validates and returns the connecting client's IP
 */
function getClientIP(){

    // Get real visitor IP behind CloudFlare network
    if (!empty($_SERVER["HTTP_CF_CONNECTING_IP"]) && validateIP($_SERVER['HTTP_CF_CONNECTING_IP'])) {
        return $_SERVER["HTTP_CF_CONNECTING_IP"];
    }

    // Get real visitor IP behind NGINX proxy - https://easyengine.io/tutorials/nginx/forwarding-visitors-real-ip/
    if (!empty($_SERVER["HTTP_X_REAL_IP"]) && validateIP($_SERVER['HTTP_X_REAL_IP'])) {
        return $_SERVER["HTTP_X_REAL_IP"];
    }

    // Check for shared Internet/ISP IP
    if (!empty($_SERVER['HTTP_CLIENT_IP']) && validateIP($_SERVER['HTTP_CLIENT_IP'])) {
        return $_SERVER['HTTP_CLIENT_IP'];
    }

    // Check for IP addresses passing through proxies
    if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {

        // Check if multiple IP addresses exist in var
        if (strpos($_SERVER['HTTP_X_FORWARDED_FOR'], ',') !== false) {
            $iplist = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
            foreach ($iplist as $ip) {
                if (validateIP($ip))
                    return $ip;
            }
        }
        else {
            if (validateIP($_SERVER['HTTP_X_FORWARDED_FOR']))
                return $_SERVER['HTTP_X_FORWARDED_FOR'];
        }
    }

    if (!empty($_SERVER['HTTP_X_FORWARDED']) && validateIP($_SERVER['HTTP_X_FORWARDED']))
        return $_SERVER['HTTP_X_FORWARDED'];

    if (!empty($_SERVER['HTTP_X_CLUSTER_CLIENT_IP']) && validateIP($_SERVER['HTTP_X_CLUSTER_CLIENT_IP']))
        return $_SERVER['HTTP_X_CLUSTER_CLIENT_IP'];

    if (!empty($_SERVER['HTTP_FORWARDED_FOR']) && validateIP($_SERVER['HTTP_FORWARDED_FOR']))
        return $_SERVER['HTTP_FORWARDED_FOR'];

    if (!empty($_SERVER['HTTP_FORWARDED']) && validateIP($_SERVER['HTTP_FORWARDED']))
        return $_SERVER['HTTP_FORWARDED'];

    // Return unreliable IP address since all else failed
    return $_SERVER['REMOTE_ADDR'];
}

/**
 * Ensures an IP address is both a valid IP address and does not fall within
 * a private network range.
 */
function validateIP($ip) {

    if (strtolower($ip) === 'unknown')
        return false;

    // Generate IPv4 network address
    $ip = ip2long($ip);

    // Do additional filtering on IP
    if(!filter_var($ip, FILTER_VALIDATE_IP))
        return false;

    // If the IP address is set and not equivalent to 255.255.255.255
    if ($ip !== false && $ip !== -1) {

        // Make sure to get unsigned long representation of IP address
        // 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;
}

我在生产节点中使用它，它工作得很好。由于大部分代码来自这里，我已经在GNU @ https://github.com/d3vdigital/whatsmyip-node下发布了一个节点

这是我使用的方法，它验证IPv4输入:

// Get user IP address
if ( isset($_SERVER['HTTP_CLIENT_IP']) && ! empty($_SERVER['HTTP_CLIENT_IP'])) {
    $ip = $_SERVER['HTTP_CLIENT_IP'];
} elseif ( isset($_SERVER['HTTP_X_FORWARDED_FOR']) && ! empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
    $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
} else {
    $ip = (isset($_SERVER['REMOTE_ADDR'])) ? $_SERVER['REMOTE_ADDR'] : '0.0.0.0';
}

$ip = filter_var($ip, FILTER_VALIDATE_IP);
$ip = ($ip === false) ? '0.0.0.0' : $ip;