NTLMv2 Authentication with nginx.

gistfile1.php

<?php

define('PROXY', 'proxy');
define('PORT', 8080);

if (!function_exists('getallheaders'))
{
  function getallheaders()
	{
		$headers = [];
		foreach ($_SERVER as $name => $value)
		{
			if (substr($name, 0, 5) == 'HTTP_')
			{
				$headers[str_replace(' ', '-', ucwords(strtolower(str_replace('_', ' ', substr($name, 5)))))] = $value;
			}
		}
		return $headers;
	}
}

$headers = getAllHeaders(); // Equivalent to apache_request_headers() to get the headers of the request.

if(!isset($headers['Authorization'])) // Check Authorization Header
{
	header('HTTP/1.1 401 Unauthorized'); // Return Unauthorized Http-Header (NTLM protocol)
	header('WWW-Authenticate: NTLM'); // Authenticcation Information (NTLM protocol)
}
else
{
	if(substr($headers['Authorization'],0,4) == 'NTLM') // Check whether Authorization Header is valid
	{
		$message = base64_decode(substr($headers['Authorization'], 5)); // Get NTLM Message from Authrization header
		if(substr($message, 0, 8) == "NTLMSSP\x00") // Check whether NTLM Message is valid
		{
			if($message[8] == "\x01") // Check whether it's type-1-NTLM Message
			{
				// $message holds the base64 encoded type-1-NTLM message
				$ch = curl_init(); // Use cURL to connect to web via proxy
				curl_setopt($ch, CURLOPT_URL, "http://www.google.com");
				curl_setopt($ch, CURLOPT_HTTPHEADER, array("Authorization: {$headers['Authorization']}"));

				curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
#				curl_setopt($ch, CURLOPT_VERBOSE, 1);
#				curl_setopt($ch, CURLOPT_HEADER, 1);

				curl_setopt($ch, CURLOPT_PROXY, PROXY);
				curl_setopt($ch, CURLOPT_PROXYPORT, PORT);
				$result = curl_exec($ch);
				$info = curl_getinfo($ch);
				curl_close($ch);
				$header = substr($result, 0, $info['header_size']);
				$body = substr($result, $info['header_size'], $info['download_content_length']-$info['header_size']);
				$c_headers = explode("\r\n", $header);
				for($i = 0; $i < (count($c_headers) - 2); $i++)
				{
					header($c_headers[$i]);
					if(substr($c_headers[$i], 0, 16) == "WWW-Authenticate")
					{
						echo 'Type 2';
						// Thats your type-2-message header Format: WWW-Authenticate: NTLM <base64-type-2-message>
					}
				}
				var_dump($result);
				var_dump($c_header);
			}
			else if ($message[8] == "\x03") // Check whether it's type-3-NTLM Message
			{
				$ch = curl_init(); // Use cURL to connect to web via proxy 
				curl_setopt($ch, CURLOPT_URL, "http://www.google.com");
				curl_setopt($ch, CURLOPT_HTTPHEADER, array("Authorization: {$headers['Authorization']}"));
				curl_setopt($ch, CURLOPT_PROXY, PROXY);
				curl_setopt($ch, CURLOPT_PROXYPORT, PORT);
				$result = curl_exec($ch);
				$info = curl_getinfo($ch);
				curl_close($ch);
				if($info['CURLINFO_HTTP_CODE'] == 200)
				{
					echo 'Type 3';
					// Authenticated
					// $msg holds the base64 encoded type-3-NTLM message (which includes username, domain, workstation)
				}
			}
		}
	}
}

?>

How is this "with nginx"? Rather should be "with PHP", as otherwise you'd be configuring some nginx config to handle NTLM...