php 获取服务器地址和客户端地址

一：服务器地址：

$host = isset($_SERVER['HTTP_X_FORWARDED_HOST']) ? $_SERVER['HTTP_X_FORWARDED_HOST'] : (isset($_SERVER['HTTP_HOST']) ? $_SERVER['HTTP_HOST'] : '');

二：客户端地址：

function getClientIp()
 {
  if (getenv ( "HTTP_CLIENT_IP" ) && strcasecmp ( getenv ( "HTTP_CLIENT_IP" ), "unknown" ))
   $ip = getenv ( "HTTP_CLIENT_IP" );
  else if (getenv ( "HTTP_X_FORWARDED_FOR" ) && strcasecmp ( getenv ( "HTTP_X_FORWARDED_FOR" ), "unknown" ))
   $ip = getenv ( "HTTP_X_FORWARDED_FOR" );
  else if (getenv ( "REMOTE_ADDR" ) && strcasecmp ( getenv ( "REMOTE_ADDR" ), "unknown" ))
   $ip = getenv ( "REMOTE_ADDR" );
  else if (isset ( $_SERVER ['REMOTE_ADDR'] ) && $_SERVER ['REMOTE_ADDR'] && strcasecmp ( $_SERVER ['REMOTE_ADDR'], "unknown" ))
   $ip = $_SERVER ['REMOTE_ADDR'];
  else
   $ip = "unknown";
  return $ip;
 }