PHP获取IP地址的多种有效方法

<?php
echo "<br>";
?>

<?php

function GetIP()
{
if(!empty($_SERVER["HTTP_CLIENT_IP"]))
$cip = $_SERVER["HTTP_CLIENT_IP"];
else if(!empty($_SERVER["HTTP_X_FORWARDED_FOR"]))
$cip = $_SERVER["HTTP_X_FORWARDED_FOR"];
else if(!empty($_SERVER["REMOTE_ADDR"]))
$cip = $_SERVER["REMOTE_ADDR"];
else
$cip = "无法获取！";
return $cip;
}
echo "<br>";
?>

方法二：
<?php
echo "<br>";
?>

<?
error_reporting (E_ERROR | E_WARNING | E_PARSE);
if($HTTP_SERVER_VARS["HTTP_X_FORWARDED_FOR"])
{
$ip = $HTTP_SERVER_VARS["HTTP_X_FORWARDED_FOR"];

}
elseif($HTTP_SERVER_VARS["HTTP_CLIENT_IP"])
{
$ip = $HTTP_SERVER_VARS["HTTP_CLIENT_IP"];

}
elseif ($HTTP_SERVER_VARS["REMOTE_ADDR"])
{
$ip = $HTTP_SERVER_VARS["REMOTE_ADDR"];

}
elseif (getenv("HTTP_X_FORWARDED_FOR"))
{
$ip = getenv("HTTP_X_FORWARDED_FOR");

}
elseif (getenv("HTTP_CLIENT_IP"))
{
$ip = getenv("HTTP_CLIENT_IP");

}

elseif (getenv("REMOTE_ADDR"))
{
$ip = getenv("REMOTE_ADDR");

}

else
{
$ip = "Unknown";

}
echo "你的IP地址是:".$ip."<br>";
?>

方法三（最简单）：
<?php
echo "<br>";
?>

<?
$iipp = $_SERVER["REMOTE_ADDR"];
echo $iipp;
echo "<br>";
?>

方法四：
<?php
echo "<br>";
?>

<?php
$user_IP = ($_SERVER["HTTP_VIA"]) ? $_SERVER["HTTP_X_FORWARDED_FOR"] : $_SERVER["REMOTE_ADDR"];
$user_IP = ($user_IP) ? $user_IP : $_SERVER["REMOTE_ADDR"];
echo $user_IP."<br>";
?>

方法五：
<?php
echo "<br>";
?>

<?
function get_real_ip()
{
$ip=false;
if(!empty($_SERVER["HTTP_CLIENT_IP"]))
{
$ip = $_SERVER["HTTP_CLIENT_IP"];
}
if (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))
{
$ips = 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 get_real_ip();
echo "<br>";
?>

方法六：
<?php
echo "<br>";
?>

<?
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;
echo "<br>";
?>