PHP获取客户端IP

function getIP()
{
if( isset($_SERVER) )
{
if( isset($_SERVER["HTTP_X_FORWARDED_FOR"]) )
{
$ip = $_SERVER["HTTP_X_FORWARDED_FOR"];
} elseif ( isset($_SERVER["HTTP_CLIENT_IP"]) ) {
$ip = $_SERVER["HTTP_CLIENT_IP"];
} elseif ( isset($_SERVER["REMOTE_ADDR"]) ) {
$ip = $_SERVER["REMOTE_ADDR"];
} else {
$ip = $_SERVER["SSH_CLIENT"];
}
} else {
if( getenv("HTTP_X_FORWARDED_FOR") )
{
$ip = getenv("HTTP_X_FORWARDED_FOR");
} elseif ( getenv("HTTP_CLIENT_IP") ) {
$ip = getenv("HTTP_CLIENT_IP");
} else {
$ip = getenv("REMOTE_ADDR");
}
}
return $ip;
}