在 PHP 中检索用户正确 IP 地址的最准确方法是什么?

问题描述

我知道有大量的 $_SERVER 变量标头可用于 IP 地址检索.我想知道关于如何使用上述变量最准确地检索用户的真实 IP 地址(众所周知没有完美的方法)是否存在普遍共识?

I know there are a plethora of $_SERVER variables headers available for IP address retrieval. I was wondering if there is a general consensus as to how to most accurately retrieve a user's real IP address (well knowing no method is perfect) using said variables?

我花了一些时间试图找到一个深入的解决方案，并根据许多来源提出了以下代码.如果有人可以在答案中戳破洞或阐明一些可能更准确的内容，我会很高兴.

I spent some time trying to find an in depth solution and came up with the following code based on a number of sources. I would love it if somebody could please poke holes in the answer or shed some light on something perhaps more accurate.

编辑包括来自@Alix的优化

 /**
  * Retrieves the best guess of the client's actual IP address.
  * Takes into account numerous HTTP proxy headers due to variations
  * in how different ISPs handle IP addresses in headers between hops.
  */
 public function get_ip_address() {
  // Check for shared internet/ISP IP
  if (!empty($_SERVER['HTTP_CLIENT_IP']) && $this->validate_ip($_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 IP addresses exist in var
    $iplist = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
    foreach ($iplist as $ip) {
     if ($this->validate_ip($ip))
      return $ip;
    }
   }
  }
  if (!empty($_SERVER['HTTP_X_FORWARDED']) && $this->validate_ip($_SERVER['HTTP_X_FORWARDED']))
   return $_SERVER['HTTP_X_FORWARDED'];
  if (!empty($_SERVER['HTTP_X_CLUSTER_CLIENT_IP']) && $this->validate_ip($_SERVER['HTTP_X_CLUSTER_CLIENT_IP']))
   return $_SERVER['HTTP_X_CLUSTER_CLIENT_IP'];
  if (!empty($_SERVER['HTTP_FORWARDED_FOR']) && $this->validate_ip($_SERVER['HTTP_FORWARDED_FOR']))
   return $_SERVER['HTTP_FORWARDED_FOR'];
  if (!empty($_SERVER['HTTP_FORWARDED']) && $this->validate_ip($_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.
  *
  * @access public
  * @param string $ip
  */
 public function validate_ip($ip) {
     if (filter_var($ip, FILTER_VALIDATE_IP,
                         FILTER_FLAG_IPV4 |
                         FILTER_FLAG_IPV6 |
                         FILTER_FLAG_NO_PRIV_RANGE |
                         FILTER_FLAG_NO_RES_RANGE) === false)
         return false;
     self::$ip = $ip;
     return true;
 }

警告的话(更新)

REMOTE_ADDR 仍然代表 IP 地址的最可靠来源.此处提到的其他 $_SERVER 变量很容易被远程客户端欺骗.此解决方案的目的是尝试确定位于代理后面的客户端的 IP 地址.出于一般目的，您可以考虑将其与直接从 $_SERVER['REMOTE_ADDR'] 返回的 IP 地址结合使用，并同时存储两者.

Words of Warning (update)

REMOTE_ADDR still represents the most reliable source of an IP address. The other $_SERVER variables mentioned here can be spoofed by a remote client very easily. The purpose of this solution is to attempt to determine the IP address of a client sitting behind a proxy. For your general purposes, you might consider using this in combination with the IP address returned directly from $_SERVER['REMOTE_ADDR'] and storing both.

对于 99.9% 的用户而言，此解决方案将完美满足您的需求.它无法保护您免受 0.1% 的恶意用户的侵害，这些用户希望通过注入自己的请求标头来滥用您的系统.如果依赖 IP 地址执行关键任务，请使用 REMOTE_ADDR，不要费心迎合代理背后的人.

For 99.9% of users this solution will suit your needs perfectly. It will not protect you from the 0.1% of malicious users looking to abuse your system by injecting their own request headers. If relying on IP addresses for something mission critical, resort to REMOTE_ADDR and don't bother catering to those behind a proxy.

推荐答案

这里有一种更简洁、更简洁的方式来获取 IP 地址:

function get_ip_address(){
    foreach (array('HTTP_CLIENT_IP', 'HTTP_X_FORWARDED_FOR', 'HTTP_X_FORWARDED', 'HTTP_X_CLUSTER_CLIENT_IP', 'HTTP_FORWARDED_FOR', 'HTTP_FORWARDED', 'REMOTE_ADDR') as $key){
        if (array_key_exists($key, $_SERVER) === true){
            foreach (explode(',', $_SERVER[$key]) as $ip){
                $ip = trim($ip); // just to be safe

                if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) !== false){
                    return $ip;
                }
            }
        }
    }
}

---

你的代码似乎已经很完整了，我看不到任何可能的错误(除了通常的 IP 警告)，我将更改 validate_ip() 函数以依赖过滤器扩展虽然:

---

Your code seems to be pretty complete already, I cannot see any possible bugs in it (aside from the usual IP caveats), I would change the validate_ip() function to rely on the filter extension though:

public function validate_ip($ip)
{
    if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) === false)
    {
        return false;
    }

    self::$ip = sprintf('%u', ip2long($ip)); // you seem to want this

    return true;
}

您的 HTTP_X_FORWARDED_FOR 代码段也可以简化为:

Also your HTTP_X_FORWARDED_FOR snippet can be simplified from this:

// 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 $ip)
        {
            if ($this->validate_ip($ip))
                return $ip;
        }
    }

    else
    {
        if ($this->validate_ip($_SERVER['HTTP_X_FORWARDED_FOR']))
            return $_SERVER['HTTP_X_FORWARDED_FOR'];
    }
}

为此:

// check for IPs passing through proxies
if (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))
{
    $iplist = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);

    foreach ($iplist as $ip)
    {
        if ($this->validate_ip($ip))
            return $ip;
    }
}

您可能还想验证 IPv6 地址.

You may also want to validate IPv6 addresses.

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