Proxy Market Reviews

how to detect proxies using various methods; it also provides crucial information on improving your online security.

HTTP message-headers are used by HTTP, the Hypertext-Transfer Protocol, to control connections or supply additional information like the browser’s version string, the system language or even dynamic content such as cookies. A HTTP message-header as defined by RFC2616 looks like this:
message-header = field-name “:” [ field-value ]
       field-name = token
       field-value = *( field-content | LWS )
       field-content = <the OCTETs making up the field-value
                        and consisting of either *TEXT or combinations
                        of token, separators, and quoted-string>

 Proxies and HTTP Headers

As proxies introduce additional functionality, they also introduce new HTTP message-header fields. One of these additional fields is stored inside the HTTP_X_FORWARD element and is used by various proxy servers to submit the IP of the client using it. Similar to this the HTTP_X_FORWARDED_FOR field is used and may be seen as an indication of a relayed connection. Using just these two elements of the HTTP header one might find references to users trying to avoid detection schemes. On the other hand, a user trying to circumvent such a measure may be advised to check for these header fields being used by his chosen proxy.

if (
      $_SERVER['HTTP_X_FORWARDED_FOR']
   || $_SERVER['HTTP_X_FORWARDED']
   || $_SERVER['HTTP_FORWARDED_FOR']
   || $_SERVER['HTTP_VIA']
   || in_array($_SERVER['REMOTE_PORT'], array(8080,80,6588,8000,3128,553,554))
   || @fsockopen($_SERVER['REMOTE_ADDR'], 80, $errno, $errstr, 30))
{
    exit(’Proxy detected’);
}