经过复杂的判断与算是的获取IP地址函数 
 
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; 
} 
 
最简单获取ip地址代码一句实例 
 
$reIP=$_SERVER["REMOTE_ADDR"]; 
echo $reIP; 
 
php获取ip的算法 
 
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; 
 
可以分出内网与外网站ip地址获取程序 
 
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[‘REMOTE_ADDR‘]); 
} 
echo getip_out(); 
 
php获取ip的算法,用了?号表达式来处理 
 
$user_IP = ($_SERVER["HTTP_VIA"]) ? $_SERVER["HTTP_X_FORWARDED_FOR"] : $_SERVER["REMOTE_ADDR"]; 
$user_IP = ($user_IP) ? $user_IP : $_SERVER["REMOTE_ADDR"]; 
 
php下获取客户端ip地址的函数
php 获取客户端的真实ipPHP 获取客户端真实IP地址多种方法小结
原文:http://www.jb51.net/article/23489.htm