PHP获取用户访问IP地址的5种方法

<?php                                                                 //方法1：
$ip = $_server["remote_addr"];
echo $ip;
 
//方法2：
$user_ip = ($_server["http_via"]) ? $_server["http_x_forwarded_for"] : $_server["remote_addr"];
$user_ip = ($user_ip) ? $user_ip : $_server["remote_addr"];
echo $user_ip;
 
//方法3：
function getrealip()
{
  $ip=false;
  if(!empty($_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 getrealip();
 
//方法4：
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 $ip ;
 
//方法5：
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;