用php来检测proxy

  能够检测大部分通过代理服务器访问的ip.
  <?php
  //beiji.com 2000.6.17
  $ip=getenv("REMOTE_ADDR");
  $v=getenv("HTTP_VIA");
  $f=getenv("HTTP_X_FORWARDED_FOR");
  $c=getenv("HTTP_XROXY_CONNECTION");
  $o=getenv("HTTP_PRAGMA");
  print'<br>REMOTE_ADDR';
  print$ip;
  if(($v=="")&&($f=="")&&($c=="")&&($o=="")){
  print"<br>not through proxy";
  }
  else{
  print"<br>through proxy";
  print'<br>http_via:';print$v;
  print'<br>http_x_forwarded_for:';print$f;
  print'<br>http_xroxy_connection:';print$c;
  print'<br>http_pragma:';print$o;
  }
  ?>