Summary of various methods to obtain the real IP address of the client in PHP

After complex judgment and calculation, the function of obtaining the IP address

function getIP() { 
if (getenv('HTTP_CLIENT_IP')) { 
$ip = getenv('HTTP_CLIENT_IP'); 
} 
elseif (getenv('HTTP_X_FORWARDED_FOR')) { 
$ip = getenv('HTTP_X_FORWARDED_FOR'); 
} 
elseif (getenv('HTTP_X_FORWARDED')) { 
$ip = getenv('HTTP_X_FORWARDED'); 
} 
elseif (getenv('HTTP_FORWARDED_FOR')) { 
$ip = getenv('HTTP_FORWARDED_FOR'); 

} 
elseif (getenv('HTTP_FORWARDED')) { 
$ip = getenv('HTTP_FORWARDED'); 
} 
else { 
$ip = $_SERVER['REMOTE_ADDR']; 
} 
return $ip; 
}

The simplest example of obtaining the IP address code

$reIP=$_SERVER["REMOTE_ADDR"]; 
echo $reIP;

The algorithm of obtaining the IP in php

if(getenv('HTTP_CLIENT_IP')) { 
$onlineip = getenv('HTTP_CLIENT_IP'); 
} elseif(getenv('HTTP_X_FORWARDED_FOR')) { 
$onlineip = getenv('HTTP_X_FORWARDED_FOR'); 
} elseif(getenv('REMOTE_ADDR')) { 
$onlineip = getenv('REMOTE_ADDR'); 
} else { 
$onlineip = $HTTP_SERVER_VARS['REMOTE_ADDR']; 
} 
echo $onlineip;

can be divided into Procedure for obtaining IP addresses from internal and external websites

function getip_out(){ 
$ip=false; 
if(!empty($_SERVER["HTTP_CLIENT_IP"])){ 
$ip = $_SERVER["HTTP_CLIENT_IP"]; 
} 
if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) { 
$ips教程 = explode (", ", $_SERVER['HTTP_X_FORWARDED_FOR']); 
if ($ip) { array_unshift($ips, $ip); $ip = FALSE; } 
for ($i = 0; $i < count($ips); $i++) { 
if (!eregi ("^(10│172.16│192.168).", $ips[$i])) { 
$ip = $ips[$i]; 
break; 
} 
} 
} 
return ($ip ? $ip : $_SERVER[&#39;REMOTE_ADDR&#39;]); 
} 
echo getip_out();

php algorithm for obtaining IP, what is used? Expression to process

$user_IP = ($_SERVER["HTTP_VIA"]) ? $_SERVER["HTTP_X_FORWARDED_FOR"] : $_SERVER["REMOTE_ADDR"]; 
$user_IP = ($user_IP) ? $user_IP : $_SERVER["REMOTE_ADDR"];

For more PHP summary of multiple methods to obtain the client’s real IP address, please pay attention to the PHP Chinese website for related articles!