PHP - Making A Poll System

So I have made an anonymous poll system but I would like to limit the possibility to vote only once from a single pc.

I think that I could store and check 3 things regarding a user that has voted:
1) $_SERVER['HTTP_CLIENT_IP']."!".$_SERVER['HTTP_X_FORWARDED_FOR']."!".$_SERVER['REMOTE_ADDR'];
2) HTTP cookie
3) Flash cookie LSO (because this contrary to the HTTP cookei can be detected in multiple browsers( (only if Flash is installed)))

But there can be a simple situation - a simple user votes one time from Firefox and after a time his IP changes (for example he uses some Mobile internet where dynamic addressing is used) . Then for some reason he wants to use Internet Explorer where Flash is not installed. In result - it is possible to vote twice.

Can anyone please suggest something regarding this?

I know there is not 100% bulletproof solution - I just want to minimise the possibility to vote more than once.

Also I am thinking about using EverCookie(undeletable cookie) but that could cause a lot of other problems.

For my A level ICT i need to create a PHP newsletter email system for which people can sign up from one page and then a admin can log in and send out the email to the people that have signed up. My problem is i also need to attach a PDF to these emails, however i cant work out how to add this into the scripts i have for the newsletter system. Even my teacher cant help me  , please can someone help me    .
The code i have is below.
admin.php
<?php
  //load configuration
  require("config.php");
  
  //connect to database
  @mysql_connect($db_server,$db_user,$db_password) or die("Database server connection failed. Check variables \$db_server, \$db_user and \$db_password in config.php");
  @mysql_select_db($db_name) or die("Selecting database failed. Check variable \$db_name in config.php");
  
  //print header
  echo $header;
?>
<h1><?php echo $title; ?> - Administration</h1>
<hr>
<?php 
  $pwd = $_GET["pwd"];

  //simple login
  if(isset($pwd) && ($pwd == $password)){
    $submit = $_POST["submit"];
    $submit_newsletter = $_POST["submit_newsletter"];
    $del = $_GET["del"];
          
    //insert new address
    if(isset($submit)){
      $name = $_POST["name"];
      $email = $_POST["email"];
      
      @mysql_query("INSERT INTO $db_table (email,name) VALUES ('$email','$name');");
      
      //error occurred
      if(@mysql_error()){
        ?><p>Inserting entry failed: <?php echo @mysql_error(); ?></p>
        <p><a href="javascript&#38;#058;history.back();">Click here to go back.</a></p><?php
      //successful
      }else{
        ?><p>Entry has been inserted successfully. <a href="admin.php?pwd=<?php echo $pwd; ?>">Click here to continue.</a></p><?php
      }
    //delete an entry
    }else if(isset($del)){
      @mysql_query("DELETE FROM $db_table WHERE id=$del;");
      
      //error occurred
      if(@mysql_error()){
        ?><p>Deleting entry failed: <?php echo @mysql_error(); ?></p>
        <p><a href="javascript&#38;#058;history.back();">Click here to go back.</a></p><?php
      //successful
      }else{
        ?><p>Entry has been deleted successfully. <a href="admin.php?pwd=<?php echo $pwd; ?>">Click here to continue.</a></p><?php
      }
    //send newsletter
    }else if(isset($submit_newsletter)){
      $sent = 0;
      $result = @mysql_query("SELECT name,email FROM $db_table ORDER BY email ASC;");
      $subject = $_POST["subject"];
      $message = $_POST["message"];
      
      ?><p>Sending emails to ...</p>
      <ul><?php
      
      //send emails one by one
      while($row=@mysql_fetch_array($result)){
        $name = $row["name"];
        $email = $row["email"];
        
        ?><li><?php echo $name; ?> (<?php echo $email; ?>) ... <?php

        if(@mail($email,$subject,$message,"From: $admin <$admin>\n")){
          ?>sent<?php
          $sent++;
        }else{
          ?>failed<?php
        }
        
        ?></li><?php
      }
      
      ?></ul>
      <p><strong><?php echo $sent; ?> emails sent.</strong> <a href="admin.php?pwd=<?php echo $pwd; ?>">Click here to continue.</a></p><?php
    //print forms
    }else{
       ?><h2>Send newsletter</h2>
       <form method="post" action="<?php echo $_SERVER["PHP_SELF"]; ?>?pwd=<?php echo $pwd; ?>">
         <table>
           <tr>
             <td>Subject:</td>
             <td><input type="text" name="subject" class="fixedwidth"></td>
           </tr>
           <tr>
             <td valign="top">Message:</td>
             <td><textarea name="message" cols="60" rows="20" class="fixedwidth"><?php echo $signature; ?></textarea></td>
           </tr>
           <tr>
             <td>&nbsp;</td>
             <td><input type="submit" name="submit_newsletter" value="Send"></td>
           </tr>
         </table>
       </form>

       <h2>Add an email address</h2>
       <form action="<?php echo $_SERVER["PHP_SELF"]; ?>?pwd=<?php echo $pwd; ?>" method="post">
         <table>
           <tr>
             <td>Name:</td>
             <td><input type="text" name="name" value="" maxlength="255"></td>
           </tr>
           <tr>
             <td>Email address:</td>
             <td><input type="text" name="email" value="" maxlength="255"></td>
           </tr>
           <tr>
             <td>&nbsp;</td>
             <td><input type="submit" name="submit" value="Submit"></td>
           </tr>
         </table>
       </form>

       <h2>Email addresses</h2>
       <table cellpadding="5" cellspacing="2">
         <tr class="header">
           <td><strong>Name</strong></td>
           <td><strong>Email address</strong></td>
           <td>&nbsp;</td>
         </tr>
         <?php
           $result = @mysql_query("SELECT * FROM $db_table ORDER BY email ASC;");
           $colored = false;

           while($row=@mysql_fetch_array($result)){
             $colored = !$colored;
             ?><tr<?php if($colored){ ?> class="colored"<?php } ?>>
               <td width="200"><?php echo $row["name"]; ?></td>
               <td width="200"><?php echo $row["email"]; ?></td>
               <td><a href="<?php echo $_SERVER["PHP_SELF"]; ?>?pwd=<?php echo $pwd; ?>&del=<?php echo $row["id"]; ?>">remove</a></td>
             </tr><?php
           }
         ?>
       </table>
       <?php
    }
  }else{
    //print login form
    echo $login;
  }
  
  //print link to news
  ?><p align="right"><a href="index.php">Newsletter</a></p><?php
  
  //print footer
  echo $footer;

  //close database connection
  @mysql_close();
?>
config.php
<?php
/* ######################## DATABASE ######################## */

  // Database server
  $db_server = "localhost";
  
  // Database name
  $db_name = "zpwebsi1_news";
  
  // Database username
  $db_user = "zpwebsi1_zac";

  // Database password
  $db_password = "powell";
  
  // Database table to store news
  // (will be created automatically)
  $db_table = "easy_newsletter";

/* ##################### CONFIGURATION ###################### */

  // Complete URL of the script
  // (begins with http://, ends with slash)
  $url = "http://www.charsfieldthreehorseshoes.co.uk/alemail.html";
  
  // Password for the administration
  $password = "admin";
  
  // Administrator email address (will be used as sender of
  // the newsletter emails)
  $admin = "zac@zpwebsite.com";

  // Title (will be displayed in the browser's header
  $title  = "Ale Mail";

  // Signature (will be inserted when creating a fresh
  // newsletter but can be changed before submitting)
  $signature  = "\n\n\n\n\n---------------------\nYou receive this email because you have registered with our newsletter $title. Click the following link to unsubscribe: $url";

/* ######################### LAYOUT ######################### */

  // Header to be used on each page
  $header = <<<EOT
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <link href="style.css" rel="stylesheet" type="text/css">
    <title>$title</title>
  </head>
  <body>
EOT;

  // Footer to be used on each page
  $footer = <<<EOT
  </body>
</html>
EOT;

  // Login form
  $login = <<<EOT
    <form action="admin.php" method="get">
      Password: <input name="pwd" type="password"> <input type="submit" value="Login">
    </form>
EOT;
?>

And index.php
<?php
  //load configuration
  require("config.php");
  
  //print header
  echo $header;
?>
<h1><?php echo $title; ?></h1>
<hr>
<?php  
  //form submitted
  if(isset($_POST["submit"])){
    //connect to database
    @mysql_connect($db_server,$db_user,$db_password) or die("Database server connection failed. Check variables \$db_server, \$db_user and \$db_password in config.php");
    @mysql_select_db($db_name) or die("Selecting database failed. Check variable \$db_name in config.php");

    $name = $_POST["name"];
    $email = $_POST["email"];
    
    //subscribe
    if($_POST["action"]=="subscribe"){
      //check if name is long enough
      if(strlen($name)<3){
        ?><p>Name must consist of at least 3 characters.</p><?php
      //check if email is valid
      }else if(!eregi("^[0-9a-z]([-_.]?[0-9a-z])*@[0-9a-z]([-.]?[0-9a-z])*\\.[a-z]{2,3}$",$email)){
        ?><p>Email address is not valid.</p><?php
      //check if email already exists
      }else if(@mysql_num_rows(@mysql_query("SELECT id FROM $db_table WHERE email='$email';"))){
        ?><p>Email address exists already.</p><?php
      //insert values
      }else{
        @mysql_query("INSERT INTO $db_table (email,name) VALUES ('$email','$name');");

        //error occurred
        if(@mysql_error()){
          ?><p>An unknown error occurred. Please try again later.</p><?php
        //successful
        }else{
          ?><p>Subscription was successful. Thank you!</p><?php
        }
      }
    //unsubscribe
    }else{
      @mysql_query("DELETE FROM $db_table WHERE email='$email';");

      //error occurred
      if(@mysql_error()){
        ?><p>An unknown error occurred. Please try again later.</p><?php
      //email not found
      }else if(@mysql_affected_rows()==0){
        ?><p>Email address not found.</p><?php
      //successful
      }else{
        ?><p>You have unsubscribed successfully!</p><?php
      }
    }
  }
?>
<form action="<?php echo $_SERVER["PHP_SELF"]; ?>" method="post">
  <table>
    <tr>
      <td>Your name:</td>
      <td><input type="text" name="name" value="" maxlength="255"></td>
    </tr>
    <tr>
      <td>Your email address:</td>
      <td><input type="text" name="email" value="" maxlength="255"></td>
    </tr>
    <tr>
      <td>&nbsp;</td>
      <td><input type="radio" name="action" value="subscribe" id="action_subscribe" checked> <label for="action_subscribe">subscribe</label>&nbsp;<input type="radio" name="action" value="unsubscribe" id="action_unsubscribe"> <label for="action_unsubscribe">unsubscribe</label></td>
    </tr>
    <tr>
      <td>&nbsp;</td>
      <td><input type="submit" name="submit" value="Submit"></td>
    </tr>
  </table>
</form>
<p align="right"><a href="admin.php">Administration</a></p>
<?php
  //print footer
  echo $footer;

  //close database connection
  @mysql_close();
?>

This topic has been moved to Miscellaneous.

http://www.phpfreaks.com/forums/index.php?topic=349747.0

Hello,

I'm trying to create a system where I can monitor where people are at on my website (so I'll be able to see which specific page their on). However, I've ran into a snag, because I have no idea where to start. There isn't an account system used so it has to be based off ip address and I only wanted to display active people within the last 15 minutes. So, I'm assuming this has to be session/cookie based, but I've never had to work with that before. I'm a complete loss and I've tried looking up tutorials online, but I'm not getting any real good results.

Could anyone point me in the right direction?

Thanks.

hello dear PHP-Fans - greetings to you - and a happy new year!!


i set up a WAMP-System on my openSuse 11.4 system.  In order to learn as much as i can bout PHP i want to do some tests and write some scripts.

Well the WAMP is allready up and running.  Now i try to give the writing access to the folder

mkdir /srv/www/

where the php-scripts should go in...

i want  to give write permission to all to all files in /srv/www

As root I generally:

mkdir /srv/www/
chown <webmaster usrername> /srv/www/

/srv/www/ should be readable and traversable by all, but only writeable by it's owner (the user designated as the webmaster.)

can i do this like mentioned above,...

Love to hear from you

greetings
db1