PHP获取客户端ip或服务器ip

<?php
function getIP(){
global $ip;
if (getenv("HTTP_CLIENT_IP"))
$ip = getenv("HTTP_CLIENT_IP");
else if(getenv("HTTP_X_FORWARDED_FOR"))
$ip = getenv("HTTP_X_FORWARDED_FOR");
else if(getenv("REMOTE_ADDR"))
$ip = getenv("REMOTE_ADDR");
else $ip = "Unknow";
return $ip;
}
?>

<?php
function real_server_ip(){
static $serverip = NULL;
if ($serverip !== NULL){
return $serverip;
}
if (isset($_SERVER)){
if (isset($_SERVER['SERVER_ADDR'])){
$serverip = $_SERVER['SERVER_ADDR'];
}else{
$serverip = '0.0.0.0';
}
}
else{
$serverip = getenv('SERVER_ADDR');
}
return $serverip;
}
?>