我知道有大量的$_SERVER变量头可用于IP地址检索。我想知道是否有一个普遍的共识，如何最准确地检索用户的真实IP地址(好知道没有方法是完美的)使用上述变量?
我花了一些时间试图找到一个深入的解决方案，并根据一些来源提出了以下代码。如果有人能在答案中找出漏洞，或者提供一些更准确的信息，我会很高兴。
edit包含来自@Alix的优化
/**
* Retrieves the best guess of the client's actual IP address.
* Takes into account numerous HTTP proxy headers due to variations
* in how different ISPs handle IP addresses in headers between hops.
*/
public function get_ip_address() {
// Check for shared internet/ISP IP
if (!empty($_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 = $ip;
return true;
}
警告之词(更新)
REMOTE_ADDR仍然表示最可靠的IP地址来源。这里提到的其他$_SERVER变量很容易被远程客户端欺骗。此解决方案的目的是试图确定位于代理后面的客户机的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，并存储两者。
对于99.9%的用户，这个解决方案将完美地满足您的需求。它不能保护您免受0.1%的恶意用户通过注入他们自己的请求头来滥用您的系统。如果某些关键任务依赖于IP地址，请使用REMOTE_ADDR，而不必费心满足代理背后的需求。
如果你使用CloudFlare缓存层服务，下面是修改后的版本
function getIP()
{
$fields = array('HTTP_X_FORWARDED_FOR',
'REMOTE_ADDR',
'HTTP_CF_CONNECTING_IP',
'HTTP_X_CLUSTER_CLIENT_IP');
foreach($fields as $f)
{
$tries = $_SERVER[$f];
if (empty($tries))
continue;
$tries = explode(',',$tries);
foreach($tries as $try)
{
$r = filter_var($try,
FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 |
FILTER_FLAG_NO_PRIV_RANGE |
FILTER_FLAG_NO_RES_RANGE);
if ($r !== false)
{
return $try;
}
}
}
return false;
}
我的回答基本上是@AlixAxel的回答的一个经过润色、完全验证和完全打包的版本:
<?php
/* Get the 'best known' client IP. */
if (!function_exists('getClientIP'))
{
function getClientIP()
{
if (isset($_SERVER["HTTP_CF_CONNECTING_IP"]))
{
$_SERVER['REMOTE_ADDR'] = $_SERVER["HTTP_CF_CONNECTING_IP"];
};
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))
{
foreach (explode(',', $_SERVER[$key]) as $ip)
{
$ip = trim($ip);
if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) !== false)
{
return $ip;
};
};
};
};
return false;
};
};
$best_known_ip = getClientIP();
if(!empty($best_known_ip))
{
$ip = $clients_ip = $client_ip = $client_IP = $best_known_ip;
}
else
{
$ip = $clients_ip = $client_ip = $client_IP = $best_known_ip = '';
};
?>
变化:
它简化了函数名(使用'camelCase'格式样式)。
它包括一个检查，以确保函数没有在代码的另一部分中声明。
它还考虑了“CloudFlare”的兼容性。
它将多个“ip相关”变量名称初始化为'getClientIP'函数的返回值。
它确保如果函数没有返回有效的IP地址，所有变量都被设置为空字符串，而不是null。
它只有(45)行代码。
我想出了这个函数，它不简单地返回IP地址，而是一个具有IP信息的数组。
// Example usage:
$info = ip_info();
if ( $info->proxy ) {
echo 'Your IP is ' . $info->ip;
} else {
echo 'Your IP is ' . $info->ip . ' and your proxy is ' . $info->proxy_ip;
}
函数如下:
/**
* 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.
*
* @since 1.1.3
*
* @return object {
* IP Address details
*
* string $ip The users IP address (might be spoofed, if $proxy is true)
* bool $proxy True, if a proxy was detected
* string $proxy_id The proxy-server IP address
* }
*/
function ip_info() {
$result = (object) array(
'ip' => $_SERVER['REMOTE_ADDR'],
'proxy' => false,
'proxy_ip' => '',
);
/*
* This code tries to bypass a proxy and get the actual IP address of
* the visitor behind the proxy.
* Warning: These values might be spoofed!
*/
$ip_fields = array(
'HTTP_CLIENT_IP',
'HTTP_X_FORWARDED_FOR',
'HTTP_X_FORWARDED',
'HTTP_X_CLUSTER_CLIENT_IP',
'HTTP_FORWARDED_FOR',
'HTTP_FORWARDED',
'REMOTE_ADDR',
);
foreach ( $ip_fields as $key ) {
if ( array_key_exists( $key, $_SERVER ) === true ) {
foreach ( explode( ',', $_SERVER[$key] ) as $ip ) {
$ip = trim( $ip );
if ( filter_var( $ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE ) !== false ) {
$forwarded = $ip;
break 2;
}
}
}
}
// If we found a different IP address then REMOTE_ADDR then it's a proxy!
if ( $forwarded != $result->ip ) {
$result->proxy = true;
$result->proxy_ip = $result->ip;
$result->ip = $forwarded;
}
return $result;
}
虽然这篇文章很老了，但这个话题仍然值得关注。所以我在我的项目中使用了另一个解决方案。我在这里找到了其他的解决方案，要么不完整，要么太复杂，难以理解。
if (! function_exists('get_visitor_IP'))
{
/**
* Get the real IP address from visitors proxy. e.g. Cloudflare
*
* @return string IP
*/
function get_visitor_IP()
{
// Get real visitor IP behind CloudFlare network
if (isset($_SERVER["HTTP_CF_CONNECTING_IP"])) {
$_SERVER['REMOTE_ADDR'] = $_SERVER["HTTP_CF_CONNECTING_IP"];
$_SERVER['HTTP_CLIENT_IP'] = $_SERVER["HTTP_CF_CONNECTING_IP"];
}
// Sometimes the `HTTP_CLIENT_IP` can be used by proxy servers
$ip = @$_SERVER['HTTP_CLIENT_IP'];
if (filter_var($ip, FILTER_VALIDATE_IP)) {
return $ip;
}
// Sometimes the `HTTP_X_FORWARDED_FOR` can contain more than IPs
$forward_ips = @$_SERVER['HTTP_X_FORWARDED_FOR'];
if ($forward_ips) {
$all_ips = explode(',', $forward_ips);
foreach ($all_ips as $ip) {
if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE)){
return $ip;
}
}
}
return $_SERVER['REMOTE_ADDR'];
}
}
谢谢，非常有用。
如果代码在语法上是正确的，这将会有所帮助。在第20行有一个{too many。这恐怕意味着没人真正尝试过。
我可能疯了，但在尝试了一些有效和无效的地址后，validate_ip()唯一有效的版本是这样的:
public function validate_ip($ip)
{
if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE) === false)
return false;
if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_RES_RANGE) === false)
return false;
if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4) === false && filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) === false)
return false;
return true;
}
