403 - Forbidden: Access is denied. On uploading CSV file or data.

Hi Bilal,

To answer your question on how to find the destination folder you need to follow these steps.

1. Check the Upload Code in Your Controller: In your ASP.NET MVC application, the destination folder for file uploads is typically specified in the controller that handles the upload logic. Look for the code where the file is being saved.

2. Determine the Physical Path of the Folder: To determine the physical path of the upload folder on your server:

   1. Use Server.MapPath in a test method to print out the exact path.

   2. Log the Path to Check: Add logging to see where the files are being uploaded. You can use Console.WriteLine.

3.  Locate the Folder on AWS EC2 Instance

   1. Connect to the EC2 Instance: Use SSH or RDP to log into the EC2 instance hosting your application.

      1. For Windows EC2 instances, use Remote Desktop.

      2. For Linux-based EC2 instances, use SSH.

   2. Check the Application Root Directory:

      1. Navigate to your website's root directory (usually inside C:\inetpub\wwwroot for IIS or /var/www/html for Linux setups).

      2. Find the folder where your application is hosted and look for the Uploads folder or whatever folder you have configured in your code.

4. Permissions for the Folder: Once you've located the folder, ensure that the permissions are set properly:

   1. For Windows:

      1. Right-click the folder → Properties → Security → Ensure that the IIS_IUSRS group or your application pool identity has Write permissions.

   2. For Linux:

      1. Use the chmod command to set the appropriate permission

5. Verify in Application Logs: You can also check your server logs (IIS logs, application logs) to see if there are any issues related to the file upload path.

 

Let me know if this helps you locate the folder!

Hi Bilal,

There might be more things that need to be checked, but that depends on your usage if you are using for not.

1. ModSecurity or WAF (Web Application Firewall) : , it might be blocking large file uploads due to security rules. You may need to whitelist your upload endpoint or modify the security rules to allow larger requests.
2. Nginx or Apache Proxy Settings (if used): If you’re running Nginx or Apache as a reverse proxy in front of IIS on AWS, ensure that the proxy’s request size limits are set correctly:
3. ASP.NET MVC Anti-Forgery Token Size: In some cases, large form posts (like uploading files) can cause issues with anti-forgery tokens. You may want to disable or adjust the token for the file upload action to see if it resolves the issue.
4. CloudFront or Load Balancer Settings (if applicable) : If you’re using AWS CloudFront or an Elastic Load Balancer (ELB) in front of your EC2 instance, ensure that they are configured to handle larger file uploads.

Hi Aman,

Thank you very much for your response. I'm glad the information was helpful.

If you've thoroughly checked points 1, 2, and 4, and all the necessary settings and limits are configured correctly, then we can focus on point 3.For point 3, if smaller files are being processed correctly, it's likely not a path issue. However, it's still a good idea to verify the destination path folder to ensure there are no hidden issues. Can you please guide how to find the destination folder.

Hi Bilal,

The issue you are facing might nbe because of server or application-level configurations.

1. IIS Request Filtering or Upload Limit: 

• Check the web.config settings for request limits. ASP.NET applications may have default file size limits that could be causing the issue.
• maxRequestLength controls the maximum size of the HTTP request in kilobytes (default is 4MB).
• maxAllowedContentLength is the size limit for uploaded files in bytes (set it according to your needs).

2. AWS Security Group and NACL Configuration

• Check the AWS EC2 security group settings. Ensure that the inbound and outbound traffic allows HTTP/HTTPS traffic from your specific IP or range.

3. File Permissions on EC2 Instance

• Ensure that the directory where files are uploaded has the correct permissions. If the application cannot write to the destination folder, it could result in a "403 Forbidden" error. Grant the necessary permissions to the application pool identity.

4. Check AWS EC2 Instance Limits

• AWS EC2 instances may have certain limits on bandwidth or data transfer rates. Review the instance’s network performance and ensure it can handle larger requests effectively.

Thanks