What is MIME type "application/vnd.noblenet-sealer"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

The MIME type application/vnd.noblenet-sealer is vendor-specific. It is used for files that have been digitally sealed for integrity and authenticity.

Files of this type are processed by proprietary software that applies a seal to secure the content. The seal may involve cryptographic checks or embedded metadata to ensure the file has not been tampered with.

The format helps systems identify and open the file with the correct application. This reduces errors when sharing or archiving secured data.

Secured Data Distribution – Ensures only authorized programs can open and verify the file.
Integrity Verification – Embeds checks to confirm that the content has remained unchanged.
Proprietary Packaging – Limits file handling to trusted software environments.

Typically, files using this MIME type use the extension NNS. For more on similar formats and MIME types, visit IANA media types.

Associated file extensions

.nns

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: application/vnd.noblenet-sealer

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="application/vnd.noblenet-sealer">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');    
    
    http.createServer((req, res) => {    
      res.setHeader('Content-Type', 'application/vnd.noblenet-sealer');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

.nns

FAQs

What software opens files with the MIME type application/vnd.noblenet-sealer?

Files with this MIME type are typically processed by NobleNet Sealer or associated proprietary software used for secure document distribution. Because the format is vendor-specific, standard viewers cannot open the .nns file without the specific client application installed.

How do I configure Apache to serve .nns files correctly?

To ensure your Apache server sends the correct headers, add the following line to your .htaccess file or main configuration: AddType application/vnd.noblenet-sealer .nns. This helps client browsers identify that the file requires a specific external application.

Why does my browser download the file instead of displaying it?

Web browsers like Chrome and Firefox do not have native support for rendering application/vnd.noblenet-sealer content. Consequently, they treat it as a generic binary file and force a download, expecting the user to open it with a local desktop application.

How do I add this MIME type to an Nginx server?

You can add the type to your mime.types file or directly inside a server block. Use the directive: types { application/vnd.noblenet-sealer nns; }. Reload Nginx afterwards to apply the changes for serving .nns files.

What does the 'vnd.' prefix mean in this MIME type?

The vnd. prefix stands for vendor, indicating that this MIME type is specific to a commercial product or company (NobleNet) rather than being a generic open standard. It distinguishes proprietary formats from standard types like application/pdf.

Can I convert an application/vnd.noblenet-sealer file to PDF?

Direct conversion is often impossible with standard tools because the file is likely encrypted or digitally sealed. You typically need to open the file in the original NobleNet software and use its internal export or print functions to save the content as a PDF.

I receive a 404.3 error on IIS when trying to access .nns files. How do I fix this?

IIS blocks unknown file extensions by default for security reasons. To resolve this, open IIS Manager, navigate to MIME Types, and add a new entry with the extension .nns and the MIME type application/vnd.noblenet-sealer.

General FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.