How to Configure CORS in IIS Using the IIS CORS Module: Step-by-Step Guide

introduction

Cross-Origin Resource Sharing (CORS) is a security feature implemented by web browsers that allows you to control which resources can be accessed based on the origin of the request. In this way, web servers are given the power to define which domains can access resources, ensuring that only trusted origins can interact with the server. In this modern era of applications where most web apps fetch data from multiple origins, CORS is crucial to managing and securing these interactions.

If CORS is not enabled or configured correctly, you will often get exceptions like “Access denied from ‘”.http://your API endpoint‘From the beginning’http://yourwebsite‘ is blocked by CORS policy. No ‘Access-Control-Allow-Origin’ header is present on the requested resource. If an opaque response satisfies your needs, set the request mode to ‘no-cors’ to fetch the resource with CORS disabled.”

way out

The IIS CORS module simplifies the configuration process for server administrators. The steps below guide you through downloading, installing, updating, and configuring the IIS CORS module. web.config file.

Installation and Configuration

You can download the IIS CORS module from the official download link. IIS CORS Module: Official Microsoft IIS Site.

Depending on your operating system, download the appropriate x86 installer or x64 installer. Installation is simple. Simply double-click the downloaded MSI and the installation will guide you through the process.

Once the IIS CORS module is installed, you can configure it using: web.config This is the file for your application. This allows you to customize the behavior of CORS to suit your application’s security and functionality requirements. Here is a basic example of how to configure CORS settings in your web.config file.

You should put this configuration below. System.Webserver Tags. Below are details for each tag used in CORS configuration.

• Activated=”true”: Enables CORS for your application.
• genesis=”https://example.com“: Specifies allowed domains.
• Allow credentials=”true”: Allows cookies to be sent with requests.
• Maximum age=”600″: The time (in seconds) that the browser will cache the CORS response.
• : Specifies the allowed HTTP methods (GET, POST, etc.).
• : Defines the headers allowed in a request.
• : Lists the headers that a browser can expose to a client.

conclusion

CORS configuration is essential for securing modern web applications that rely on resources from other origins. The IIS CORS module helps simplify the process by ensuring that interactions are only with trusted domains. The IIS CORS module provides flexibility and control over CORS settings, enabling the cross-origin functionality you need while helping protect your application from potential cross-origin threats.