Linux, Apache, MySQL, PHP

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.0/jquery.min.js"></script>
<div class="row">
  <div class="col-md-12">
    <div class="box box-default">
      <div class="box-header with-border">
        <h3 class="box-title">Report Per Office</h3>
      </div>
      <div class="box-body">
        <div class="col-md-12">
          <h4>Project Procurement Management Plan (PPMP) <hr >
        </div>
        <div class="col-md-1">
          Office:
        </div>
        <div class="col-md-4">
              <select class="selectpicker" data-live-search="true" name="office_from" data-width="auto" required >
              <option>--Select Reponsible Office--</option>
                          <?php 
                            $q = "SELECT * FROM `office_code_dept`";
                            $r = mysqli_query($conn,$q);
                            while($row = mysqli_fetch_assoc($r)){
                            $off_desc = $row['off_name']; 
                           ?>
                          <option value="<?php echo $off_desc;?>"><?php echo $off_desc; ?></option>
                          <?php 
                            }
                          ?>
                        </select>
                      </div>
                      <div class="col-md-1">Year:</div>
                      <div class="col-md-4"><input type="number" min="1990" max="3000" name="tax_year" class="form-control" style="text-align: center;" value="<?php echo date('Y'); ?>"></div>
                      <div class="col-md-2"><input type="submit" name="search" value="Search" class="btn btn-primary btn-block">
                      </div>
                      <div class="col-md-12"><br></div>
            </h4>

          <table class="table table-bordered" id="dynamic_field">
            <thead>
                 <tr>
                    <th width="7%" rowspan="2" style="text-align: center;">Code</th>
                    <th width="27%" rowspan="2" style="text-align: center;">General Description</th>
                    <th rowspan="2" width="5%"><button type="button" name="add" id="add" class="btn btn-success">class="fa fa-plus"></button></th>

                 </tr>

              </thead>
              <tbody>
                 <tr>
                    <td align="center">
                      <input type="text" name="account_code[]" class="form-control account_num" readonly>
                    </td>
                    <td>
                      <select class="form-control selectpicker" data-live-search="true" name="account_name[]" required>
                      <option></option>
                      <?php 
                        $account = mysqli_query($conn,"SELECT chart_of_account.acoount_no, chart_of_account.account_title from chart_of_account inner join account_group_tbl on chart_of_account.account_group = account_group_tbl.account_name where account_group_tbl.account_type = 'Expense'");
                        while($acc = mysqli_fetch_assoc($account)){
                          $account_no = $acc['acoount_no'];
                          $account_title = $acc['account_title'];
                      ?>
                      <option value="<?php echo $account_title; ?>" data-acc="<?php echo $account_no; ?>">
                        <?php echo $account_title ; ?>   
                      </option>
                    <?php } ?>
                    </select>
                    </td>
                    <td></td>
                 </tr>
              </tbody>
           </table>
      </div>   
    </div>
  </div>
</div>
<script>
   $('select[name="account_name[]').change(function()
    {
     $('.account_num').val($('select[name="account_name[]"] option:selected').data('acc'));
    });
</script>
<script>
$(document).ready(function(){
  var i=1;
  var chart_add = '<tr id="row_chart'+i+'"><td align="center">                      <input type="text" name="account_code[]" class="form-control account_num" readonly></td><td><select class="form-control selectpicker" data-live-search="true" name="account_name[]" required>                      <option></option><?php $account = mysqli_query($conn,"SELECT chart_of_account.acoount_no, chart_of_account.account_title from chart_of_account inner join account_group_tbl on chart_of_account.account_group = account_group_tbl.account_name where account_group_tbl.account_type = 'Expense'");while($acc = mysqli_fetch_assoc($account)){$account_no = $acc['acoount_no'];$account_title = $acc['account_title'];?><option value="<?php echo $account_title; ?>" data-price="<?php echo $account_no; ?>"><?php echo $account_title ; ?>                    </option><?php } ?></select></td><td><button type="button" name="remove_chart" id="'+i+'" class="btn btn-danger remove_chart"></button></td></tr>';
  $('#add').click(function(){
    i++;
    $('#dynamic_field').append(chart_add);
    $('.selectpicker').selectpicker('render');
     $('select[name="account_name[]').change(function()
       {
          $('.account_num').val($('select[name="account_name[]"] option:selected').data('acc'));
        });
    });
  $(document).on('click', '.remove_chart', function(){
    var button_id = $(this).attr("id"); 
    $('#row_chart'+button_id+'').remove();
  });
  
});
</script>

I am using yii2 basic application template and developed an application.
I am using VPS server for hosting this application on a domain on Host gator.

Now I want that only office users should access this application i.e, (while accessing this application using domain, .htaccess file should check if the IP accessing this domain is allowed to have access. If yes, then that IP should be able to have access, else that IP should see a message containing Access Denied).

If we do this then how to specify IP addresses in .htaccess file. Do we need to specify the static IP addresses of the employees in our organization?

If we write the foll code in .htaccess,

order allow,deny
allow 192.168.1.3
deny from all

Here, which IP address to be specified? Do we need to specify the Public IP or routers Private IP or static IP?

How to accomplish this?


Does IP address change from network to network. When I connect to my WiFi, i get my public IP. So this IP is unique in the world?

<?php

 if ($_SERVER['REQUEST_METHOD'] != 'POST') {
 	header("Location: index.php");
 	exit();
 }

 $ch = curl_init();
 curl_setopt($ch, CURLOPT_URL, 'https://ipnpb.sandbox.paypal.com/cgi-bin/webscr');
 curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
 curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
 curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
 curl_setopt($ch, CURLOPT_POST, 1);
 curl_setopt($ch, CURLOPT_POSTFIELDS, "cmd=_notify-validate&" . http_build_query($_POST));
 $response = curl_exec($ch);
 curl_close($ch);
 
 
 file_put_contents("test.txt", $response);