ARDUINO web server login
<p>I have created a website that will be hosted on an Arduino web server.This is used to convert speech to text, send it back to the Arduino server. The received string is then printed on an LCD. Basically, it is a voice based notice board that can be used in an institution.</p>

<p>To allow access to this website to specific users only, I have created a login form that can be seen in this link:
<a href="http://176.32.230.47/noticeboard.com/php/index.php" rel="nofollow">http://176.32.230.47/noticeboard.com/php/index.php</a></p>

<p>After successful login, it redirects to a page that looks something like this:
<a href="http://i.stack.imgur.com/N42Xa.jpg" rel="nofollow">the mainpage which is in-turn used to access one of the Arduino web servers in the LAN </a></p>

<p>As evident in this main-page, the buttons for the classes will be used to redirect to the Arduino web-server in that particular class. Let me say the ip address of one such server is 192.168.1.5. The problem is, I don't want other users on the same LAN to be able to access the website hosted on the Arduino by typing it's ip address in their browsers. </p>

<p>How can I make this page on the Arduino web server accessible only after login? It shouldn't be in such a way that by simply typing the ip address of the Arduino, one can access the web page hosted on it. 
I don't know if Arduino web server can hold php files so that I can include the following piece of code: </p>

<pre><code>session_start();
        if($_SESSION['id']==null)

        header("Location:"name_of_the_file_i_want_to_redirect_to.php");
</code></pre>

<p>If the Arduino web-server can be accessed by anyone on the LAN, the whole objective of this log in system is lost.
Kindly help me.</p>

<p>PS: The login page and the main-page( the one that is used to re-direct to the appropriate website served by one of the Arduinos in the LAN) are hosted on a different server.   </p>